While setting up Office 365 I ran into an issue with the Active Directory Azure Synchronization tool, at the configuration stage I was presented with the error “Set-CoexistenceConfiguration was unable to modify the source properties. See the event logs for more detailed information”
When looking in the Application event log there was a few messages about a SQL “could not be found in the forest”
Long story short I have no idea why but I just pressed the retry button and the process completed fine.