Issues after you have run Defraggler
I ran Defraggler on my Windows Vista/7 PC and now I've lost one or more System Restore points.
This is a known issue with Windows Vista/7 and third-party defragmentation tools such as Defraggler. The problem occurs when the amount of disk space set aside for System Restore is too low.
Advanced users can clear out old System Restore points ('volume shadow copies') to make more room using this procedure.