Transferring Meeting Ownership From an Ex-Employee Can Be Hard Work
Neither Outlook nor Teams includes a transfer meeting ownership feature for user calendars. Moving meetings owned by an ex-employee to give someone else the ownership requires manual intervention to find and reschedule meetings. Administrators can cancel future meetings for a user. In this article, we explore how to generate a report of meetings that might need to be rescheduled. https://office365itpros.com/2025/04/03/transfer-meeting-ownership/Duplicate Mail User Objects Created for Guest Accounts
The February 2025 EX1015484 incident explains why mail user objects with duplicate SMTP addresses are created for guest accounts. That’s a problem because Exchange Online can’t route messages to objects with duplicate email addresses. Fortunately, you can find out if any duplicates exist in your tenant with some PowerShell. It's a good opportunity to remind ourselves of the relationship between Entra ID guest accounts and Exchange Online mail user objects. https://office365itpros.com/2025/03/28/ex1015484-problem/
Setup CatchAll-Mailbox for specific domain in Exchange
Hi, I want to introduce a CatchAll-Mailbox, meaning that all messages sent to non-existant recipients shall be redirected to a specific Mailbox. The basic idea is to introduce a rule that redirects all incoming messages and make an exception for recipients who are member of a Dynamic Group that contains all existing Mailboxes. To prevent exchange from instantly blocking the message and instead process the rules, i set the Accepted Domain to internal relay. Now i want to make this whole thing domain-specific, meaning it should only apply for unknown recipients of specificdomain.com. I tried to introduce a recipient-matches-pattern-condition but that didnt work. How can i set this up?
5.3.4 Maximum Body Parts error makes no sense
So I have one user who is plagued with one of the weirdest problems I've ever known in 30+ years of working with exchange - this is on Office365 She is sending emails from Outlook on Windows but then getting an NDR: Delivery has failed to these recipients or groups: email address here Your message is larger than the size limit for messages. Please make it smaller and try sending it again. Diagnostic information for administrators: Generating server: GV1PR02MB8281.eurprd02.prod.outlook.com email address here Remote Server returned '554-5.3.4 Content conversion limit(s) exceeded 554 5.3.4 STOREDRV.Submit.Exception:ConversionFailedException; Failed to process message due to a permanent exception with message [BeginDiagnosticData]Content conversion: Maximum number of body parts (250) per message exceeded ConversionFailedException: Content conversion: Maximum number of body parts (250) per message exceeded[EndDiagnosticData]' That's not the weird part, the weird part is as follows: 1) Any other user can send the exact same message with no problem whatsoever 2) If I run an office repair (full online) or uninstall and reinstall office, then the problem goes away and her emails send again - for a short time, after about 20-30 emails they all start failing again with the above error. 3) None of the failing messages show up in exchange logs at all that I can find, ones that succeed I can see, ones that fail for other valid reasons I can see, but these 5.3.4 emails are just not in the logs at all, it seems like the server rejects them even before they enter mail flow logging. This is a largish and complex email they are trying to send, it does have a lot of inline images and some tables that I would expect to run the email up to around 30-40 parts (not sure how to check it). When this email is generating the 5.3.4 she can still send basic emails, it's only these complex ones that fail - but it's not the email that is the problem, other staff have been sending the same email in bulk (we are a PR company, it's a weekly mailer we send out to journalists) with no issues whatsoever, and as stated if we repair or reinstall office they temporarily send and then suddenly start failing again.
Hidden Group and Hidden Group Membership
Hi everyone! I have come across a requirement where the client would like to use an excel spreadsheet, a service account and application registration to manage group membership for a confidential group. They would like to create a group from which the members cannot leave, see other team members and cannot see the group itself. Now, I have the concept of the flow with me but for the life of me, I cannot get around to finding/configuring a group that meets the requirement. Have you guys come across this sort of scenario? Group Configuration: Users should not be able to view the group Users should not be able to view members of the group Users should not be able to leave the group Thanks in advance.Microsoft Announces Tenant-Level External Recipient Rate Limit for Exchange Online
In an announcement that will surprise many, Microsoft announced the introduction of a tenant-wide external recipient rate limit for Exchange Online tenants to roll out starting on March 3, 2025. The new limit is designed to stop bad actors using Exchange Online as a spam platform. Microsoft says that its telemetry indicates that the new TERRL will not impact many tenants, but that fact is worth checking for any organization. https://practical365.com/tenant-wide-external-recipient-rate-limit/
Deleted Items in a Shared Mailbox
In O365/Exchange Online when a user deletes an item from a shared mailbox it goes to the user's deleted items not the shared mailbox's deleted items. Has anyone found a way to have them go to the shared mailbox's deleted items? I have seen that Microsoft recommends a registry change but that doesn't solve the problem. In today's world people may be just as likely to use their phone or Outlook on the web.Another Nail in the Exchange Web Services Coffin
Exchange Web Services (EWS) will retire in October 2026. Tenants that still need to use EWS must explicitly set EWSEnabled to true in the organization configuration. If they don’t, the previous rule that allows mailboxes enabled for EWS to function won’t work. The change is part of the preparation for the phase-out of EWS. To help, we’ve written a script to send email to administrators listing accounts still enabled for EWS. https://office365itpros.com/2025/02/21/ewsenabled-tenant-setting/Processing Multiple Message Attachments with the Microsoft Graph PowerShell SDK
Many examples are available online to explain how to add a single attachment to messages using the Microsoft Graph PowerShell SDK. Here we look at the principles behind how to add attachments (one or many) to messages before sending them with the Send-MgUserMail cmdlet. Get the principles right and you’ll never go wrong! https://office365itpros.com/2025/02/19/add-attachments-email/
