Person A shared their calendar with Person B via an email message, Person B has full access to Person A calendar but this isn’t reflected in Exchange, so this access cannot be seen by administrators, I have checked Exchange admin portal and PowerShell, both dont see these permissions despite Person B showing me they have full access.

How do I find out how many mailboxes in my tenant have these ghost permissions and also how do I remove access to a mailbox that Exchange believes is not there?

It’s removed from outlook, yes, but you still need to remove permissions unless you want to still be a deleagate…

Feel free to express your feelings to Microsoft. Commenting here is fine, but they won’t do anything to improve matters if they don’t understand the reasons why the current implementation causes problems for end users.

No, it is not useful, especially in an enterprise organiztion.

When you also add the permission to “SendAs” and you are in a hybrid configuration, it essentially breaks the process.

The choice to allow auto-mapping is fine. The inability to have that choice outside of powershell is an absolute nightmare for any enterprise environment,

I think it’s functionality of its time. When Outlook introduced automapping (2007 maybe?), it was to fix a problem. Most of the time people want access to a mailbox and don’t worry so much about removing permissions. So it is what it is. Not great but useful.

If it “automaps” when you grant permission, it should “auto un-map” when you remove the permission.

This is not a difficult topic to understand at all. It doesn’t matter if it is 3 mailboxes or 300, the automap behavior is useful, but poorly implemented.