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Import Bulk PST to Office 365 Step by Step | Stellar Migrator for Outlook

GiulianoDeLuca — Tue, 28 Jul 2026 10:03:37 GMT

Learn how to import bulk PST files to Office 365 (Exchange Online) step by step using Stellar Migrator for Outlook. This tutorial walks you through automating the migration of multiple PST mailboxes to Exchange Online — no manual uploads, no scripting.

Stellar Migrator for Outlook automates bulk PST-to-Office 365 migration, letting you map source PSTs to target Office 365 mailboxes (Primary, Archive, or Public Folder), apply filters, and run the whole job with minimal effort — without worrying about duplicate emails. It's a reliable way to move legacy mailboxes into Office 365.

Using a CSV file, you can migrate unlimited PST files to Office 365 users from the same system or across networked systems. The software also supports incremental migration, so you can resume or re-run a job and only new items get imported — no duplicates, no reprocessing what's already migrated.

Learn more: https://www.stellarinfo.com/import-pst-to-office-365.php

Exchange Online PowerShell Updates to 3.10.1 to Fix CBA

TonyRedmond — Mon, 27 Jul 2026 09:33:55 GMT

Microsoft rushed out version 3.10.1 of the Exchange Online management PowerShell module to fix a problem with certificate-based authentication. It seems like a change in an internal Microsoft identity platform caused the tokens issued after a successful connection to Exchange Online to not authorize the execution of further cmdlets. To their credit, Microsoft fixed the issue, but is this the kind of thing that should be caught in testing?

https://office365itpros.com/2026/07/27/exchange-online-management-3-10-1/

Apple Mail EWS sync intermittent after EwsEnabled=True + AppID allow list

stringworks — Thu, 23 Jul 2026 17:15:28 GMT

We're a small Microsoft 365 Business tenant (Exchange Online Plan 1/2 mix). One user's Apple Mail (macOS, Exchange/EWS account) intermittently stops syncing new mail — Connection Doctor shows a healthy green "Connection and login to server succeeded," but Get New Mail/manual fetch and forced Sync All Accounts return nothing new, while the same mail is already present via ActiveSync on the same user's iPhone/iPad. Symptoms recur every 1–3 days after temporarily resolving.

Troubleshooting completed so far:

- Confirmed autodiscover/External URL correctly resolves to outlook.office365.com/EWS/Exchange.asmx

- Confirmed EWS enabled at the mailbox level (Manage email apps in admin center)

- Found EwsEnabled was blank/null at the org level — set to $true via Set-OrganizationConfig

- Configured EwsAllowedAppIDs to include Apple's app ID (f8d98a96-0999-43f5-8af3-69971c7bb423, "Apple Internet Accounts")

- Fully removed and re-added the Mac Mail account after the above org-level change

- Restarted the Mac, tried DNS changes (8.8.8.8/8.8.4.4), ruled out router-level filtering

- Verified no antivirus/VPN/security software on this Mac's network

Despite all this, the issue persists intermittently. Notably, a second mailbox on the same tenant, used with Apple Mail on a different Mac (different macOS version, different physical location/network), does NOT experience this issue — so it doesn't appear to be a blanket tenant-wide EWS disruption.

Given Apple Mail's continued reliance on EWS ahead of the October 2026 phased disablement, and Microsoft's acknowledgment that Apple Mail for Mac is a heavy EWS consumer they're working with Apple to migrate to Graph, I'm wondering:

1. Could this be related to the ongoing "scream test" EWS disruption testing Microsoft has mentioned, and if so, is there a way to check whether a specific mailbox has been included in that testing?

2. Any known differences in EWS session/connection handling between macOS versions that could explain one Mac being affected and not the other?

3. Anything else worth checking tenant-side (throttling policies, CAS mailbox settings, conditional access rules) that could apply per-mailbox rather than tenant-wide?

Happy to provide EWS usage report data or run any diagnostic commands if it helps others hitting the same thing before October.

account only remote wipe device

adsnow — Tue, 21 Jul 2026 02:05:02 GMT

Hello,

My o365 account is E3. My phone is android, I installed outlook on my phone.

I tested to wipe the outlook on my phone with my admin account, but after I click the "account only remote wip1e device", it showed "Saving in progress", then showed a red "X".

The client is Outlook for iOS and Android, client type is outlook not EAS.

Do I need more steps to wipe outlook on my phone? or a role/permission is missed?

Thanks and regards,

Adsnow

Reminder: Exchange 2016 and 2019 ESU Program Ends in October 2026

The_Exchange_Team — Mon, 20 Jul 2026 18:10:45 GMT

Over the last several weeks we have received several questions about possible extension of the Exchange Server 2016/2019 ESU program past October 2026. After all, in our original Exchange 2016/2019 ESU announcement we said that there would be no extensions, but then we ended up creating a Period 2 Exchange ESU program that is scheduled to end with October 2026. We are just about at the mid-point of Period 2 Exchange ESU now.

There will be no further extension of Exchange 2016/2019 ESU program timeline. Once October 2026 ends, there will be no further updates for Exchange 2016/2019, even if you currently have a Period 2 ESU.

If your organization still uses Exchange 2016 or 2019 in production:

See Upgrading your organization from current versions to Exchange Server SE | Microsoft Community Hub – which lays out the path for how to migrate to Exchange SE if you plan to keep Exchange on-premises.
Why “in-place upgrade” from Exchange 2019 to Exchange SE is low risk | Microsoft Community Hub – which explains why in-place upgrade from Exchange 2019 CU14/CU15 to Exchange SE RTM is not a significant technological change and is low risk.

Please review Microsoft Exchange Online and Exchange Server Licensing FAQs especially "What is Exchange Server Subscription Edition (SE) and how is it licensed?” section. Exchange 2019 and Exchange SE licensing requirements are the same.

The Exchange Server Team

Reference Architecture for an On-Premises AI Assistant for Microsoft Exchange.

Vinay_Prakash — Mon, 20 Jul 2026 08:07:51 GMT

Bringing Secure AI Capabilities to On-Premises Microsoft Exchange

Many organisations continue to operate Microsoft Exchange within their own data centres because of regulatory requirements, data-residency policies, security considerations, operational dependencies, or the need to maintain complete control over sensitive email information.

At the same time, users increasingly expect Artificial Intelligence to help them manage growing email volumes, understand long conversation threads, locate information quickly, analyse attachments, and prepare relevant responses.

This creates an important question:

Can organisations introduce AI-assisted email capabilities without migrating their on-premises Exchange environment or sending email data to public AI services?

With the right architecture, the answer is yes.

The opportunity for AI in on-premises Exchange

Users spend a significant amount of time reading lengthy email chains, searching for previous discussions, identifying action items, reviewing attachments, and preparing responses.

An AI-powered email assistant can help reduce this effort while continuing to operate within the organisation’s controlled infrastructure.

Such a solution can be integrated with Microsoft Exchange through an Outlook Web App, or OWA, Add-In. The Add-In provides AI-assisted capabilities within the familiar Outlook Web interface and can be centrally deployed to selected users or Active Directory groups by the Exchange administrator.

The purpose is not to replace Exchange or change the way emails are managed. Instead, it introduces an intelligence layer that helps authorised users interact more efficiently with the email information they are already permitted to access.

Key capabilities of an AI-powered Exchange Email Assistant

1. Email and conversation summarisation

The assistant can summarise an individual email or an entire conversation thread.

Instead of reading every message in a long chain, the user can receive a structured summary covering:

The purpose of the conversation.
Important decisions and commitments.
Key action items.
Deadlines and pending responses.
Relevant information available in attachments.

The summarisation process can consider both incoming and sent messages so that the complete context of the conversation is preserved.

2. Contextual draft reply generation

The assistant can prepare a suggested response based on the complete email thread and the user’s instructions.

Users may select an appropriate tone, such as:

Formal.
Neutral.
Technical.

The generated response is placed in the user’s Exchange Draft folder or displayed for review within the OWA Add-In.

A critical control is that the AI assistant does not independently send the email. The user remains responsible for reviewing, editing, approving, and sending the response.

This human-review approach helps organisations adopt AI while retaining accountability over external and internal communications.

3. Natural-language mailbox search

Traditional mailbox search generally depends on exact keywords, sender names, subjects, or date filters.

An AI-enabled search experience allows users to search their mailbox using natural-language questions, such as:

“Find emails received last month regarding the infrastructure renewal.”
“Show unread emails from the finance team that require my approval.”
“Find the discussion where the customer confirmed the delivery date.”
“Summarise emails from a particular sender concerning the purchase order.”

The solution can combine semantic search with traditional keyword-based search to improve the relevance of results.

Users can also apply filters such as sender, subject, date range, read or unread status, and conversation thread.

4. Attachment analysis and OCR

Important information is often contained within email attachments rather than the email body itself.

An on-premises AI assistant can process supported documents, including:

PDF files.
Microsoft Word documents.
Microsoft Excel files.
Scanned documents.
Image-based attachments.

Optical Character Recognition, or OCR, can be used to extract information from scanned or image-based documents.

The extracted content can then support email summarisation, contextual draft generation, and mailbox search.

For example, a user may ask the assistant to prepare a response based on the commercial terms or delivery date mentioned in an attached document.

Maintaining strict mailbox privacy

Mailbox privacy is one of the most important architectural considerations for an enterprise AI email assistant.

Each user must only be able to access and process emails from their own authorised mailbox. Information retrieved from one user’s mailbox must never become available to another user.

This isolation should be enforced across every layer of the solution, including:

User authentication.
Exchange access tokens.
Application sessions.
Search indexes.
Vector embeddings.
AI prompts and responses.
Cache and temporary data.
Audit logs.

The backend should validate the authenticated user and verify mailbox ownership for every request made to Exchange.

Where vector search is used, mailbox data should be stored in user-isolated collections, partitions, or namespaces. This helps prevent cross-user retrieval at the data layer rather than relying only on controls within the user interface.

Operating without public cloud AI services

For organisations with strict security or data-sovereignty requirements, the AI models and supporting components can be deployed within the customer’s infrastructure.

A fully on-premises architecture may include:

A locally hosted Large Language Model.
An on-premises embedding model.
A re-ranking model.
A vector database.
A keyword-search engine.
A backend API layer.
An OCR or document-intelligence service.
A secured OWA Add-In.
Integration with Active Directory.
Audit, monitoring, and administrative controls.
The entire solution can operate within an internal network without sending email content, attachments, prompts, or generated responses to public AI platforms.

This model can also support air-gapped environments where internet access is either restricted or completely unavailable.

Centralised deployment and administration

The OWA Add-In can be deployed centrally through Exchange administration controls.

Administrators can assign the Add-In only to selected users or security groups. Employees who are not assigned the solution will not see the AI assistant within their Outlook Web interface.

Administrative controls may include:

User and group assignment.
Enabling or disabling individual AI features.
Summarisation-only mode.
Draft-generation controls.
Attachment-size restrictions.
Session and retention policies.
Model and performance settings.
Usage monitoring.
Audit logs.
Resource utilisation monitoring.

These controls allow organisations to begin with a limited group of users and gradually extend the solution after validating performance, security, and user adoption.

Security and governance considerations

Introducing AI into an enterprise email environment requires more than deploying a language model.

The complete solution should be designed around security, privacy, governance, and responsible AI principles.

Important considerations include:

Authentication and authorisation

The solution should integrate with the organisation’s existing identity infrastructure, such as Active Directory, and enforce role-based access controls.

Encryption

Email content, attachments, indexes, logs, and other sensitive information should be encrypted both in transit and at rest.

Data retention

Organisations should clearly define whether AI prompts, generated summaries, and draft content are retained.

In privacy-sensitive environments, generated content may remain available only for the active session and should not be permanently stored by the AI application.

Auditability

The system should record relevant operational events, such as the user identity, requested function, timestamp, and processing status.

Depending on the organisation’s policy, the actual email or generated response content may be excluded from audit logs.

Human oversight

AI-generated responses should be treated as suggestions. The user must review and approve them before sending.

The assistant should also disclose its limitations and avoid presenting uncertain outputs as confirmed facts.

Performance and capacity

On-premises AI processing depends on available compute, memory, storage, and GPU resources.

The architecture should account for:

Number of concurrent users.
Average mailbox size.
Volume and size of attachments.
Expected response time.
Model size.
Search-index growth.
OCR processing requirements.
High availability and backup requirements.

A practical adoption approach

Organisations do not need to introduce all capabilities at once.

A controlled proof of concept can begin with a limited number of users and a defined set of features.

A practical implementation sequence may include:

Phase 1: Email summarisation

Start with individual email and conversation-thread summaries. This provides immediate value while keeping the initial architecture relatively focused.

Phase 2: Contextual draft replies

Introduce draft generation with mandatory user review and clearly defined tone controls.

Phase 3: Attachment processing

Enable OCR and document parsing for supported attachments.

Phase 4: Intelligent mailbox search

Index authorised mailbox content and introduce natural-language search with strict per-user isolation.

Phase 5: Wider deployment

After security testing, performance validation, and user feedback, extend the solution to additional departments or user groups.

Conclusion

Organisations operating on-premises Microsoft Exchange do not necessarily need to choose between maintaining control over their email environment and adopting AI-assisted productivity capabilities.

A carefully designed on-premises AI email assistant can support email summarisation, contextual draft preparation, attachment analysis, and natural-language mailbox search while keeping sensitive information within the organisation’s infrastructure.

The most important success factors are not limited to the AI model itself. Identity controls, mailbox isolation, human approval, auditing, infrastructure sizing, and data-governance policies are equally important.

For organisations evaluating private, sovereign, or air-gapped AI, on-premises Exchange can become an effective starting point for introducing practical AI capabilities in a secure and controlled manner.

Connect with us to implement this solution in your organization.

About the Author

Vinay Prakash is the CEO of Glorious Insight and an Ex Microsoft Employee. He works with organisations on Data, Artificial Intelligence, Microsoft cloud technologies, enterprise applications, and secure on-premises AI solutions.

For technical discussions related to private or on-premises AI adoption, he can be reached at:

Email: email address removed for privacy reasons

The Demise of the OWA Light Client

TonyRedmond — Fri, 17 Jul 2026 09:46:02 GMT

On July 8, Microsoft said that they will retire the OWA Light client for Exchange Server in August 2026. But what happened to the OWA Light client for Exchange Online? It seems like Microsoft announced the retirement of OWA Light for Exchange Online in June 2024, but didn’t really make the fact clear in a blog post about consumer accounts. In any case, you can’t run OWA Light for Exchange Online, even if you wanted to.

https://office365itpros.com/2026/07/17/owa-light-retirement/

Exchange 2019 + ADFS is it possible to configure ModernAuth for third-party Android mail clients?

DeadAuroraUz — Fri, 17 Jul 2026 05:18:21 GMT

Hello,

Our organization operates under Uzbekistan's data localization and banking secrecy regulations, which require customer and corporate data — including email — to remain on infrastructure physically located within the country and under direct regulatory oversight. This precludes the use of cloud-hosted mail services such as Microsoft 365/Exchange Online, and requires a fully on-premises Exchange deployment with local identity federation (AD FS) instead of Azure AD.

Environment:
Exchange Server 2019 CU14, single server (MX01), pure on-premises.
AD FS is registered as an AuthServer (Type: ADFS), no Azure AD / hybrid tenant involved.
The AuthServer is configured correctly: AuthorizationEndpoint and TokenIssuingEndpoint are populated, IsDefaultAuthorizationEndpoint: True, and DomainName points to our mail domain. Realm/ServiceName are configured as well.

Symptom:
The native iOS Mail client (account added manually, no MDM profile) correctly redirects to our AD FS login page on first setup — the full Modern Auth flow works.

A third-party EAS client (Nine by NitroDesk, Android) never receives an OAuth challenge at all — it falls back to Basic authentication.

Get-ActiveSyncVirtualDirectory/Set-ActiveSyncVirtualDirectory in this build simply has no -OAuthAuthentication parameter (unlike EWS/OAB).

Log finding:
When testing with the Nine client, the following was captured in the Exchange HttpProxy/Eas logs:

S:ServiceCommonMetadata.OAuthError=Flighting is not enabled for domain 'webmail.<domain>'. S:ServiceCommonMetadata.OAuthErrorCategory=OAuthNotAvailable

Questions:

What exactly controls "Flighting" for EAS OAuth in a pure on-prem Exchange 2019 CU14 + AD FS scenario (no Azure AD)? Is there a documented, supported way to enable it (New-FlightOverride? something else)?
Is EAS Modern Auth even supported for an arbitrary/generic OAuth client (not Apple, not Outlook) in this scenario, or is it effectively an allowlist limited to specific client_ids (Apple Native Mail / Outlook)?
How does native iOS Mail get redirected to AD FS without ever receiving an authorization_uri in the EAS/Autodiscover 401 challenge — is there an undocumented discovery path (e.g., hardcoded per registered client_id)?

Thank you in advance for any insight.

Cross-Tenant Message Recall and Duplicate DDG Detection Enhance Exchange Online Messaging

TonyRedmond — Wed, 15 Jul 2026 08:45:38 GMT

Last week, the Exchange development team announced two interesting developments. Stopping duplicate dynamic distribution groups and cross-tenant message recall. Preventing tenants from creating duplicate DDLs saves service resources and might make tenants easier to manage. The real value is in cross-tenant message recall, which solves a problem by allowing users to recall messages delivered outside their tenant. The facility only works if the receiving tenant allows, but nothing can be done for messages delivered outside Microsoft 365.

https://office365itpros.com/2026/07/15/cross-tenant-message-recall/

How to Check Distribution Lists for Activity Over the Last 90 Days

TonyRedmond — Wed, 15 Jul 2026 08:44:31 GMT

The new Get-MessageTraceV2 cmdlet can fetch 90 days of message trace data, which means that we can check for inactive distribution lists using data for the last 90 days instead of being constrained to the last 10 days. This is done by running fetches for nine batches of traffic, each covering ten days.

Distribution lists are still important to Exchange Online and Microsoft 365, and it’s good to know which distribution lists are in active use (and how much traffic they get) and which are not. All done with PowerShell.

https://office365itpros.com/2026/07/09/inactive-distribution-list-2026/

Released: July 2026 Exchange Server Security Updates

The_Exchange_Team — Fri, 24 Jul 2026 18:41:35 GMT

Microsoft has released Security Updates (SUs) for vulnerabilities found in:

Exchange Server Subscription Edition (SE)
Exchange Server 2019
Exchange Server 2016

SUs are available for the following specific versions of Exchange Server:

Exchange SE RTM
Exchange Server 2019 CU14 and CU15 (to access, organization must be enrolled into the Period 2 ESU program)
Exchange Server 2016 CU23 (to access, organization must be enrolled into the Period 2 ESU program)

The July 2026 SUs address vulnerabilities responsibly reported to Microsoft by security partners and found through Microsoft’s internal processes.

These vulnerabilities affect Exchange Server. Exchange Online customers are already protected from the vulnerabilities addressed by these SUs and do not need to take any action other than updating any Exchange servers or Exchange Management tools workstations in their environment.

More details about specific CVEs can be found in the Security Update Guide (filter on ‘Server Software’ under Product Family for Exchange SE and ‘ESU’ under Product Family for Exchange 2016 and 2019).

Check for presence of legacy Exchange security groups

While not directly related to our July 2026 SU release, we wanted to call out that Exchange Health Checker script will now also check for the presence of very old, deprecated Exchange Server security groups, namely Exchange Domain Servers and Exchange Enterprise Servers. Those groups have been deprecated since Exchange 2007, should not be in use, and should be deleted as they might provide more permissions than modern Exchange security groups. Please see related documentation here.

Customers who have removed last on-premises Exchange Server from their organizations should also check for the presence of those groups and delete them to help prevent their possible abuse. Note that if you no longer have any Exchange servers on premises, you might want to perform a more comprehensive Active Directory cleanup as per this article.

Remove CVE-2026-42897 mitigations after installation

Installing the July 2026 update does not automatically remove already applied CVE-2026-42897 mitigations. Therefore, once you install July SU, you should:

If mitigation was applied using Exchange Emergency Mitigation (EM) Service:

Remove the mitigation M2.1.0 IIS rules.

If mitigation was applied using the downloadable EOMT script https://aka.ms/UnifiedEOMT:

Roll back the mitigation.

Exchange 2016 and 2019 updates are available only under the Period 2 ESU program

Exchange Server 2016 and 2019 are out of support. Only customers who enrolled in the Period 2 Extended Security Update (ESU) program are eligible to receive Exchange Server 2016 and 2019 security updates released between May and October 2026.

If you are not part of the Period 2 ESU program, migrate to Exchange Server Subscription Edition (SE) to keep receiving the latest security updates.

If you have already purchased the Period 2 ESU and need information on accessing the latest Security Updates, please contact us by sending an email to ExchangeandSfBServerESUInquiry@service.microsoft.com.

Known issues with this release

Wrapper messages appear in shared mailbox inbox in hybrid environments | Microsoft Support

Update installation

The following update paths are available:

Inventory your Exchange Servers to determine which updates are needed using the Exchange Server Health Checker script. Running this script will tell you if any of your Exchange Servers are behind on updates (CUs, SUs, or manual actions).
Install the latest CU. Use the Exchange Update Wizard to choose your current CU and your target CU to get directions.
Re-run the Health Checker after you install an update to see if any further actions are needed.
After setup is completed, please reboot the server and check that all Exchange services have started properly. If some services are in a disabled state, that indicates that something interrupted installation of the update. Please see the Workaround 1 in this article.
If you encounter errors during or after installation of Exchange Server, run the SetupAssist script. If something does not work properly after updates, see Repair failed installations of Exchange Cumulative and Security updates. Also please see File version error when you try to install Exchange Server updates.

FAQs

When CVE-2026-42897 mitigation was released, there were several reported known issues. Are those addressed in this update?
Yes, when July 2026 SU is installed and mitigation is removed, mitigation known issues should be resolved too.

If we update some of our servers but cannot update others, can servers that will not receive update stay with CVE-2026-42897 mitigations? Is it OK to have some servers updated and some still using mitigations?
You can continue using mitigations on any servers that you cannot update to July 2026 SU (or newer). But note that known issues from mitigations will continue to apply to those servers. Additionally, after applying this update, Office Online Server (OOS) integration with Exchange Server might not function as expected until all Exchange servers in the organization have been updated.

Our organization is in Hybrid mode with Exchange Online. Do we need to do anything?
Exchange Online is already protected, but this SU needs to be installed on your Exchange servers, even if they are used only for management purposes. If you change the auth certificate after installing an SU, you should re-run the Hybrid Configuration Wizard.

The last SU/HU we installed is a few months old. Do we need to install all SUs in order to install the latest one?
SUs are cumulative. If you are running a CU supported by the SU, you do not need to install all SUs or HUs in sequential order; simply install the latest SU. Please see this blog post for more information.

Do we need to install SUs on all Exchange Servers within our organization? What about ‘Management Tools only’ machines?
Our recommendation is to install SUs on all Exchange Servers and all servers and workstations running the Exchange Management Tools to ensure compatibility between management tools clients and servers. If you are trying to update the Exchange Management Tools in the environment with no running Exchange servers, please see this.

Our organization does not have the Exchange 2016 and 2019 Period 2 ESU. How can we get current Exchange 2016 or 2019 updates?
Since Exchange 2016 and 2019 are now out of support, only customers who have enrolled into the Period 2 ESU program (which is valid between May and October 2026) can obtain Exchange 2016 or 2019 updates released after May 2026. For all other customers still running Exchange 2016 or 2019, we recommend that you upgrade your organization to Exchange SE as soon as possible.

Documentation may not be fully available at the time this post is published.

This post might receive future updates; they will be listed here (if available).

The Exchange Server Team

Unauthorized: You don't have permission to access this page or perform this action

BINODMAHARJAN — Tue, 14 Jul 2026 06:24:41 GMT

I frequently encounter an 'Unauthorized' error when attempting to manage Distribution Lists in the Exchange Admin Center, even while logged in with Global Administrator or Exchange Online Administrator privileges. Is this a known widespread issue, or is it specific to the configuration of these individual tenants?

Exchange Server to Exchange Online Migration: A Pre-Migration Readiness Checklist

Bharat-Bhushan — Sat, 11 Jul 2026 10:24:43 GMT

Over the years, I have worked on numerous Exchange Server to Exchange Online migration projects alongside Exchange administrators, IT teams, and MSPs. One consistent pattern I have noticed is that most migration issues do not originate during the migration itself — they surface because of gaps in pre-migration readiness. This checklist reflects what I have found most useful before starting any Exchange to Exchange Online migration.

Inventory and Assessment
Before touching any migration tooling, run a full inventory of your on-premises Exchange environment. This includes the Exchange Server version (2013, 2016, 2019), the number of mailboxes, database sizes, public folders, shared mailboxes, archive mailboxes, and any resource mailboxes such as rooms and equipment. Many teams also forget to document their distribution groups, dynamic distribution groups, and mail-enabled contacts. All of these need to be accounted for before you begin.

2. Active Directory and Entra ID Readiness

Check that your Active Directory is clean: no duplicate UPNs, no lingering objects, and no ambiguous legacy Exchange attributes. Verify that Microsoft Entra Connect (formerly AAD Connect) is installed, configured, and synchronizing without errors. Confirm the UPN suffix used in AD matches a verified domain in your Microsoft 365 tenant. Attribute mismatches between on-premises AD and Entra ID are one of the most common causes of post-migration issues with authentication and mail flow.

3. Mail Flow and DNS

Document all current MX records and any third-party mail filtering (SEG, anti-spam appliances). Plan whether you will cut over MX during the migration or keep a hybrid mail flow via Exchange connector. Verify SPF, DKIM, and DMARC records are in place for each domain. Applications and devices that use on-premises SMTP relay also need to be identified early — these often get missed and cause disruption after the migration window.

4. Licensing and Tenant Configuration

Confirm you have sufficient Exchange Online licenses assigned or ready to assign before the migration starts. Review your tenant for any conditional access policies that may block newly migrated users. Check the Microsoft 365 admin center for any service health issues that could affect the migration window. Also confirm your tenant's default accepted domains and any aliases that need to be added.

5. Coexistence and Hybrid Considerations

If you are running a hybrid migration (which is the recommended approach for most organisations with more than a few hundred mailboxes), confirm the Hybrid Configuration Wizard has been run and that the hybrid connector tests pass. Free/busy lookup, OAB distribution, and cross-premises message tracking should all be tested before you move any mailboxes. A common oversight is failing to validate OAuth configuration for modern authentication in hybrid — this affects calendar sharing and delegate access after migration.

6. Data and Backup

Before migrating any mailbox, verify that a recent backup of your Exchange databases exists and is recoverable. If you are running a DAG, confirm all database copies are healthy and no replay queues are building up. It is also worth checking the size and age of any archive mailboxes — large archives can significantly extend migration time and should be planned for separately.

What patterns have you seen in your environments? Are there specific pre-migration steps that have saved (or cost) you the most time? Happy to discuss further.

i need my existing exchange mail policies and everything properly configure

Alhootcenter — Sat, 11 Jul 2026 09:08:51 GMT

all configuration i need set properly have any cmd]

Cross-Tenant Message Recall in Exchange Online

The_Exchange_Team — Fri, 10 Jul 2026 15:38:58 GMT

Since we released cloud-based Message Recall in April 2023 (see Cloud-based Message Recall in Exchange Online), we’ve continued to expand where and how recall works – including support for Outlook on the web and mobile, recipient recall notifications, a maximum recallable message age, and support for external round-trip routing (see Exchange Online Message Recall Updates).

Until now, all these capabilities shared one boundary: Message Recall only worked within a single tenant. Today, we’re pleased to announce one of our most requested cross-organization enhancements:

Cross-Tenant Message Recall, controlled by a tenant admin allow list

The intra-tenant boundary

By design due to privacy concerns, Message Recall operates within the Exchange Online service boundary, and until now it has been limited to intra-tenant messages – those where the sender and the recipients belong to the same Microsoft 365 tenant. When a sender tried to recall a message they had sent to recipients in a different tenant, the recall would fail, even between organizations that work closely together and trust one another.

Customers told us this was a gap. Partners, subsidiaries, and affiliated organizations that collaborate daily across tenant boundaries wanted the same recall experience they already had inside their own tenant.

Introducing cross-tenant Message Recall

With Cross-Tenant Message Recall, a tenant admin can add other Microsoft 365 tenants to an allow list. Once a tenant is on the list, senders from those allow-listed tenants can recall messages they’ve sent to recipients in the receiving tenant – just as they would for an intra-tenant recall.

Control sits with the receiving tenant – the organization whose users received the messages. A cross-tenant recall is only honored when the receiving tenant’s admin has explicitly allow-listed the sender’s tenant. This keeps the receiving organization in full control of which external tenants are permitted to recall messages from its users’ mailboxes. The feature is disabled by default; no cross-tenant recall occurs until an admin adds at least one tenant to the allow list.

How it works

Consider two organizations that work together, Contoso and Fabrikam, both of whom are hosted in Microsoft 365:

A Contoso admin adds Fabrikam’s tenant to Contoso’s cross-tenant recall allow list.
A sender at Fabrikam recalls a message they previously sent to a recipient at Contoso.
Because Contoso has allow-listed Fabrikam, the recall is honored and processed like a standard recall against the Contoso recipient’s mailbox.

If Fabrikam is not on Contoso’s allow list, the recall fails and the Fabrikam sender will see in the recall status report that the message can’t be recalled across organizations. Allow-listing governs inbound recalls into the receiving tenant, so each organization decides independently which external tenants it trusts to recall messages from its mailboxes.

Configuring with Exchange Online PowerShell

Admins can configure these settings using Exchange Online PowerShell.

Enable or disable cross-tenant message recall for the tenant. Setting this parameter to $True turns on the capability; $False (default) turns it off:

Set-CrossTenantRecallConfiguration -CrossTenantRecallEnabled [$true | $false]

Specify external tenants to add or remove from the allowed list. Add the tenant IDs of the organizations you trust to perform recalls:

Set-CrossTenantRecallConfiguration -AllowedSenderTenantIds @{Add="<tenantId 1>","<tenantId 2>"}; {Remove="<tenantId 1>","<tenantId 2>"}

What senders and recipients see

When a sender in an allow-listed tenant recalls a message, recipients in the receiving tenant experience the recall exactly as they would an intra-tenant recall. If the receiving tenant has enabled recipient recall notifications, those notifications apply to cross-tenant recalls as well. If the sender’s tenant is not on the receiving tenant’s allow list, the sender receives a notification that the message can’t be recalled across organizations.

Availability

Cross-Tenant Message Recall will start to deploy to worldwide, GCC, GCC High, DoD and Microsoft 365 operated by 21Vianet starting mid-August, completing by mid-September. We hope you’ll find this enhancement useful, and we look forward to your feedback.

Microsoft 365 Messaging Team

How to Check Distribution Lists for Activity Over the Last 90 Days

TonyRedmond — Thu, 09 Jul 2026 09:18:20 GMT

https://office365itpros.com/2026/07/09/inactive-distribution-list-2026/

Upcoming retirement of OWA Light in Exchange Server

The_Exchange_Team — Tue, 28 Jul 2026 16:04:10 GMT

We are announcing our plan to retire and disable the OWA Light experience in Exchange Server in a future update. OWA Light was created for a much earlier era of the web, when browser support, bandwidth, and accessibility technologies were very different from today. Going forward, we want to invest in modern Outlook on the web experience that provides the cross-browser, accessible, and security-focused experience.

Organizations that still rely on OWA Light must move users to the standard Outlook on the web experience and review any internal guidance, bookmarks, training material, helpdesk scripts, or accessibility workflows that reference OWA Light.

This is how OWA Light looks like:

What is changing

In an upcoming Exchange Server update (estimated in August 2026), we plan to disable and remove the OWA Light experience. After that change is introduced, users will no longer be able to choose or be redirected to OWA Light and should use the modern Outlook on the web experience instead.

This announcement applies to Exchange Server (on-premises). We announced deprecation of OWA Light in August 2024.

Why we are making this change

OWA Light served customers well for many years. It was designed for older browsers, slower connections, and scenarios where a simplified web interface helped users access mail in environments that could not support the full Outlook Web App experience.

The web has changed significantly since OWA Light was introduced. Modern browsers are more capable and more consistent, network conditions have improved for many customers, and security landscape has changed significantly. Maintaining a separate legacy OWA Light experience increases complexity. Each additional content rendering path, control surface, and compatibility layer must be evaluated as we strengthen defenses against modern web threats.

We recommend that Exchange Server administrators use this time to identify and prepare any users, processes, or documentation that still depend on OWA Light.

To block OWA Light right away, you can create or update an existing OWA mailbox policy:

Set-OwaMailboxPolicy -OwaLightEnabled $false

Make sure that the OwaMailboxPolicy is assigned to all mailboxes. You can assign a OwaMailboxPolicy by using the Set-CasMailbox -OwaMailboxPolicy <Name> cmdlet.

Additionally, disable the OWA Light selection menu on the OWA logon page. You can do that by running:

Set-OwaVirtualDirectory -LogonPageLightSelectionEnabled $false

More information can be found in the Set-OwaMailboxPolicy and Set-OwaVirtualDirectory documentation.

Summary

OWA Light was an important compatibility experience when the web needed it. Today, the full Outlook on the web experience is the right place for us to focus. Retiring OWA Light will help reduce legacy surface area, simplify ongoing engineering work, and allow us to continue improving the experience customers use every day.

The Exchange Server team

Impact of Reduced DigiCert SSL Certificate Validity on Exchange Hybrid Environment

Zohaib_Yousuf — Tue, 07 Jul 2026 17:50:31 GMT

DigiCert is reducing certificate validity periods because of new industry requirements approved by the CA/Browser Forum. This is not a DigiCert-only decision all public Certificate Authorities must follow these limits.

DigiCert is making this change to align with the CA/Browser Forum’s Ballot SC081v3: Introduce Schedule of Reducing Validity and Data Reuse Periods. This ballot sets a timeline for all Certificate Authorities (CAs) to reduce TLS certificate validity from 398 days to 200 days in 2026, 100 days in 2027, and 47 days in 2029.

Impact on Microsoft Exchange Hybrid

For environments like Hybrid (Exchange Server SE Hybrid with Edge servers):

You'll need to renew your public SSL certificate more frequently.
Manual renewal processes will become increasingly difficult.
Consider implementing certificate lifecycle automation where supported.
Existing certificates remain valid until they expire; the new limits apply to newly issued or renewed certificates.

In Hybrid environment (Exchange Server SE, Exchange Hybrid, multiple Mailbox servers, Edge servers, and DigiCert public SSL certificates):

No need to rerun the Hybrid Configuration Wizard (HCW) solely because you renewed the SSL certificate, provided the renewed certificate uses the same subject name/SANs and is assigned to the required Exchange services.
The primary impact is operational: you'll need a robust and preferably automated certificate renewal and deployment process across your Mailbox servers, Edge servers, and any load balancers to keep pace with the shorter certificate validity periods.

Problem with EMS console, Exchange Toolbox console and permission to serialize tokens

Seiun — Tue, 30 Jun 2026 07:55:53 GMT

Hi,

we setup fresh Windows Server 2025 and install Exchange 2019 with all updates for Server and Exchange. Then we made Upgrade In-Place to Exchange Subscription Edition but problems remained.

After installation:

Cannot launch "Exchange Toolbox console". Expand console in progress and crash. Error:
FX:{714FA079-DC14-470f-851C-B7EAAA4177C1}
Type is not resolved for member 'Microsoft.Exchange.Configuration.MonadDataProvider.MonadDataAdapterInvocationException,Microsoft.Exchange.Configuration.ObjectModel, Version=15.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.
Exeption type: System.Runtime.Serialization.SerializationException
Exception stack trace:
at Microsoft.ManagementConsole.Internal.IMessageClient.ProcessRequest(Request request)
at Microsoft.ManagementConsole.Executive.RequestStatus.BeginRequest(IMessageClient messageClient, RequestInfo requestInfo)
at Microsoft.ManagementConsole.Executive.SnapInRequestOperation.ProcessRequest()
at Microsoft.ManagementConsole.Executive.Operation.OnThreadTransfer(SimpleOperationCallback callback)
EMS console. When it runs...

VERBOSE: Connecting to ex01.domain.com.

New-PSSession : [ex01.domain.com] Connecting to remote server ex01.domain.com failed with the following error message : The WinRM client cannot process the request. It cannot determine the content type of the HTTP response from the destination computer. The content type is absent or invalid. For more information, see the about_Remote_Troubleshooting

Help topic.

At line:1 char:1

+ New-PSSession -ConnectionURI "$connectionUri" -ConfigurationName Micr ...

+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

+ CategoryInfo : OpenError: (System.Manageme....RemoteRunspace:RemoteRunspace) [New-PSSession], PSRemotingTransportException

+ FullyQualifiedErrorId : -2144108297,PSSessionOpenFailed

But If i run this command on localy on server

New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri http://ex01.domain.com/PowerShell/ -Authentication Kerberos

everything is ok.

Snapin: Add-PSSnapin Microsoft.Exchange.Management.PowerShell.SnapIn - works.

3. Search mailbox

When I run: Get-MailboxSearch I get error: Get-MailboxSearch : The requesting account does not have permission to serialize tokens.

AD Exchange server computer account is member of:

Domain Computers
Exchange Install Domain Servers
Exchange Servers
Exchange Trusted subsystem
Managed Availability Servers

So exchange computer account doesn't belong to:

Domain Admins
Schema Admins
Enterprise Admins
Organization Management

I created a new user account: Admin123 and added it to

local server Administrators group
Discovery Management group
Domain Users
Server Management

but Get-MailboxSerach give the same error.

Could somebody help to solve these problems?

Tanks in advance

Tom

MAM policies are not directly applicable to Outlook for on-premises Exchange users.

Zohaib_Yousuf — Sat, 27 Jun 2026 18:53:10 GMT

Microsoft Intune App Protection (MAM) policies are not directly supported for Outlook when the mailbox is hosted on an on-premises Exchange environment.