Hi Ultradmin,
As for the issue, I would like to confirm the following things:
1. Do you mean you have decommissioned the Exchange server, and you set proxy address for users in ADSI Edit?
2. Regarding “2. Manually setting the O365 Immutable ID - Uniqueness error - SourceAnchor”, do you run the cmdlet before activating the Dirsync in the portal?
3. Do you install the latest version of Dirsync via http://go.microsoft.com/fwlink/?LinkID=278924? If not, please uninstall the old one and install a new one.
If you need have a bit details regarding the sync status, you can use the FIM shell: “C:\Program Files\Windows Azure Active Directory Sync\SYNCBUS\Synchronization Service\UIShell\miisclient.exe”
to check if there is any error. We can click the red part in the following first screenshot and click Details to get the detailed information about the issue. After doing that, you can provide the error message or screenshots about the details here for further troubleshooting. The following screenshots are just for your reference.
Thanks,
Johnny Zhang