Restrict creation of calendars
Hello all, I have been searching for a possible way to restrict the creation of sub calendars by end users. Not meaning restrict sharing or editing but creating another calendar by a user. Invariably, this is done by a supervisor/manager for some kind of vacation calendar or similar, and when/if they leave, all that data is lost if they didn't have us save the data to a shared mailbox calendar or something. If they weren't able to create sub calendars in the first place, then we could create a nice departmental shared calendar from the get-go and just assign permissions as needed. Thanks in advance
Configuring / Publishing S/MIME X.509 Certificates in M365
Hi, we have the possibility to gather free S/MIME Certificates. Since we are Cloud-Only in a M365 E1-License I wonder, how I could make use of that. Since we don't have a AD/ADDS Server to collect and sync S/MIME Certificates, I wonder how it is possible to publish those within a Cloud-Only Situation. All Setup-Guidelines from Microsoft refer to a ADDS Server and no reference on what to Do when Cloud-Only. Does anyone here have an idea to follow suite and make those Certs available (especially in OWA)?
Allowing normal users to delegation mailbox
Hi, We have a request to allow normal users to delegate their own mailboxes to other users. Following a call with Microsoft normal users can delegate folder and not the mailbox therefore requiring any administrator to make the change. Has anyone come up with a process which allows a normal user delegate via a PowerApp or Power Automate? Regards Mike
Performance Issues with Outlook When Delegating Large Mailboxes (Exchange Online)
Hello! We're using Exchange Online, and most users access their mail through the Outlook (classic) desktop app. A common scenario in our organization is that users need temporary access to a coworker’s mailbox when that person is out on PTO. We typically grant this via mailbox delegation (Read and Manage + Send As), and the mailbox remains a standard UserMailbox, not converted to a shared mailbox. The issue: When the delegate accesses the mailbox, Outlook often becomes sluggish or unresponsive, presumably due to syncing the delegated mailbox — these are usually large (30–40 GB). We've noticed major performance degradation during this sync process. What I’ve Tried: Unchecked "Download Shared Folders" (Account Settings > Account Settings> Change > More Settings > Advanced) Adjusted Offline Cached Exchange Mode to sync fewer months Unfortunately, these haven't resolved the issue. My Questions: Is there a way to delegate access without triggering a full sync of the mailbox data to Outlook? (Users are not open to switching to OWA as they rely heavily on Outlook for their primary mailbox.) What’s the best practice for temporarily granting access to large mailboxes in Exchange Online without impacting Outlook performance? Any insights or workarounds would be greatly appreciated! Thanks in advance! -AdamExchange Online Moves Closer to Dumping EWS
Microsoft is introducing a Dedicated Exchange Hybrid App to facilitate the transition away from EWS to use Graph API requests for rich hybrid coexistence (free/busy, Mail Tips, and user photos). The plan involves the creation of an Entra ID app to hold EWS permissions (stage 1) followed by Graph permissions (stage 2). Everything has to be complete by October 1, 2026, because that’s when EWS goes away. https://office365itpros.com/2025/04/22/dedicated-exchange-hybrid-app/Send admin notifications on x number of messages from an email address
Hi, We're having a problem with a repeat spam/phishing offender that recycles email addresses from a particular domain. Because the email address is new it hasn't had a chance to be picked up by blacklists, so it doesn't get picked up as spam. We can't block on content, subject or sender because it all changes so for these campaigns we're relying on user reports to give us the heads up. We also can't block the domain because we receive legitimate email from the domain also. I'd like to change this so we can hit them before users notice and possibly whilst the spam campaign is in flight but I'm unsure as to how to go about it. Is there a rule or other setting I can configure which sends notifications to specific e-mail addresses if, say 100 emails were received from any email address (or from a specific domain?) within an hour, or 5 hours? I don't see how I can configure such a rule in mailflow rules so I'm guessing this might be somewhere else. There's an element of us likely being falsely alerted to marketing campaigns, but hopefully it's configurable enough that we can limit it down to only applying this against a specific sender domain, or adding a new custom mailflow rule which will lower the likelihood of false positives. Many thanks, - Lsward
Cross forest Distribution Group list expansion
We have two forests in a 2-way trust. On each forest there's an Exchange 2016 Organization installed. On one forest a Distribution group has been created with users from both the forests, in ADUC we see the membership correctly for all the users. On the Exchange Console of that Forest opening the DG we can see only the "local" users and the SID for the remote one. Sending an email to the DG it only delivers to local forest's users. Why Exchange Server doesn't expand the DG membership as the ADUC does and deliver emails to all recipient ? Do we have to replicate remote Forest's Users as local contacts ? thanks
Quarantine new outlook connections
I am wanting to know if there is a way to quarantine a new connection from desktop outlook to exchange much like in the mobile section of the EAC with the Exchange ActiveSync Access Settings. We have defined a rule to quarantine for outlook but it will only apply for mobile devices. We are wanting any new device mobile or desktop to require an approval.
