Using Classic Outlook on Windows for personal email, calendar, and contact management
cedricc,
Where are you seeing the Global Address Book? If that is in the Portal, is it EAC or some other section? What I am seeing for Aliases is to go to the portal https://admin.microsoft.com/ then to Users, Active Users, and then click on the account and see the Aliases there (see image below). Does that show the same you are seeing in the Global Address Book?
I checked with the team about PR_PROFILE_USER_MANAGED_ALIASES_W. It is stored in the registry of the profile encoded so we cannot see it with Regedit. There is an internal tool called PeekProfile and it is supposed to show it but I never found the aliases using that tool. The bug for the Reply All Operation Failed says that the max aliases Outlook could handle was 30. If you still repro and can remove some aliases down lower than 30 and test please do and see if that helps. The Outlook Team was supposed to remove this part of the feature until the alias issue could be fixed so we should not be seeing the issue as far as I know. I still want to make sure we are accounting for the aliases wherever they are stored though.