With the latest version of the Windows Azure Directory Synchronization tool (DirSync) – version 1.0.6862.0000, available from http://go.microsoft.com/fwlink/?LinkID=278924, there has been a change in the way to manually start a directory synchronization with your Office 365 tenant.
Previously, you had to launch the DirSyncConfigShell.psc1 and then run Start-OnlineCoexistenceSync.
Now, you have to open a PowerShell command prompt and import the module (Import-Module DirSync) before running the command Start-OnlineCoexistenceSync
NOTE don’t forget to run the PowerShell window with the Run As Administrator, either you will get an error message WARNING: Event logging may fail. The current user () is not a member of the Local Administrators group on this computer.