The Data Deduplication service enables the deduplication and compression of data on selected volumes in order to optimize disk space used. If this service is stopped, optimization will no longer occur but access to already optimized data will continue to function. Fix: (1) GPO: Computer Configuration\Windows Settings\Security Settings\System Services!Data Deduplication Service (2) REG: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\ddpsvc!Start