Problem: You wan't to disable or enable DirSync a couple of minutes after disabling or enabling it and you encounter:

PS C:\Users\bas.INTERN.000> Set-MsolDirSyncEnabled -EnableDirSync $false
 
Confirm
Continue with this operation?
[Y] Yes  [N] No  [S] Suspend  [?] Help (default is "Y"): y
Set-MsolDirSyncEnabled : You cannot turn off Active Directory synchronization.
At line:1 char:1
+ Set-MsolDirSyncEnabled -EnableDirSync $false
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : OperationStopped: (:) [Set-MsolDirSyncEnabled], MicrosoftOnlineException
    + FullyQualifiedErrorId : Microsoft.Online.Administration.Automation.DirSyncStatusChangeNotAllowedException,Micros
   oft.Online.Administration.Automation.SetDirSyncEnabled

Solution: Wait anywhere from a few hours up to 72+ hours () as the previous change hasn't taken hold yet.

Sources:

• You cannot turn off Active Directory synchronization
• Directory synchronization for Office 365, Azure, or Intune can't be activated or deactivated (KB2654338).