A couple of interesting issues that can occur between DirSync and Office 365, especially during a Cutover Migration.
1) If an on-site user is not syncing correctly with their cloud account, you can simply reset their immutable ID to get them syncing again (you get their on premises immutable ID via the Synchronisation Server Manager application (miisclient.exe)). Once you have this ID, set the cloud object to use the same ID using the following PowerShell command (after connecting to the MSOL service using Connect-MsolService):
get-msoluser -userprincipalname | set-msoluser -immutableid <“ID” retrieved from miisclient.exe>
2) If you get mailboxes that aren’t syncing correctly, or users stuck on “Pending” – it is probably because their X400/X500 addresses are getting in the way. The error will look something like this:
Exchange: Exchange server “/o=ExchangeLabs/ou=Exchange Administrative Group (FYDIBOHF65NGHTJ)/cn=Configuration/cn=Servers/cn=DB3RG54GB564” was not found. Please make sure you typed the name correctly.
To fix it, simply remove their X400/X500 addresses on the on-premise Exchange and force a resync in DirSync.
If you’re having any further issues with your 365 deployment, please don’t hesitate to get in touch with the team here at Program Framework.