Written by Thomas Speekenbrink
When you don't see all users in the Offline Address Book (OAB), then you might need to make some changes in the Offline Address Book. But changes to the OAB are not directly visible as the Offline Address Book is normally only updated once a day (at 05:00 local time).
Follow this KB article if you need the OAB to be updated directly, so you can start linking users in the Exchange (Online) Synchronizer.
- Open a connection to the Exchange Server (ie. Remote Desktop)
- Open the Exchange Management Shell (EMS)
- Start this command: Get-OfflineAddressbook | Update-OfflineAddressbook
- Restart the Background Intelligent Transfer Service in services.msc on the Exchange server
- Start this command: Get-ClientAccessServer | Update-FileDistributionService
Wait until it's done, then try to load the External Users again