KB ID 0001372 Problem Last week I had a client report that ‘some’ of his users were getting this popup repeatedly, every time they launched Outlook. The Microsoft Exchange administrator has made a change that requires you quit and restart Outlook   This popup is usually seen during migrations, when mailboxes are being migrated, (or have just been migrated.) But you should only ever see it once. Solution I had recently retired the client’s old Exchange Server (Exchange 2007)  So I assumed something must have been pointed at the old server,  the client also reported that Recreating the Outlook profile also cured the problem. Which added weight to my theory. I guessed (correctly as it happens) that the problem was the Public Folders on the old server. The client wasn’t using them, but I thought, the migrated users might still be trying to connect to them, I tried to cure the problem by forcing the clients NOT to look for Public Folders with the following registry key; HKEY_CURRENT_USER > Software > Microsoft > Exchange > Setup Create 32 Bit DWORD: HasPublicFolders Value: 0 (Zero) Unfortunately that didn’t fix the problem, (in my case, however, some people reported it did solve theirs). I know from experience that public folders settings used to be defined, on the mailbox database, so I checked all the mailbox database attributes, and found the problem. To view your Mailbox Database Attributes you need to look pretty deep into Active Directory, which means using ADSIEdit. When launched, connect to the ‘Configuration’ context. Configuration > CN=Services > CN=Microsoft Exchange > CN=your organisation name > CN=Administrative Groups > CN=Exchange Administrative Group > CN=Databases > CN=your database name > Properties > Locate MSEXCHHomePublicMDB, and remove any value set. At this point I rebooted the Exchange Server, and the affected clients, and the problem was resolved. Related Articles, References, Credits, or External Links...