Hi David,
I will help to troubleshoot this issue:
I suggest you use Identity Manager to check related logs:
1. Open Identity Manager by double-clicking miisclient.exe. Its location depends on your version of the Directory Synchronization tool:
a. 32-bit: Program Files\Microsoft Online Directory Sync\SYNCBUS\UIShell
b. 64-bit: Program Files\Microsoft Online Directory Sync (Microsoft Azure Directory Sync)\SYNCBUS\Synchronization Service\UIShell.
2. For every synchronization, three lines of logs will be records here:
If we change one user’s UPN in local AD, and this change is synced to Windows Azure AD (Office 365) successfully, the sync status is “success”, and the number for Updates is “1”. Therefore, I suggest you check the following points:
Use PowerShell to force DirSync, and then check if the status for each line is “success”.
Is the number for Updates is “1”?
Is there any synchronization errors?
You can click each line, and then post three screenshots in the forum. We can help you analyze it.
Thanks,
Jerry