I'm using Piriform Speccy from Windows 98, 2000, XP and 7 (and now 10) and I haven't got any problem with.
Speccy had a good UI, a lots of options (smart defrag, full defrag, weekly defrag) and It is really fast.
I thinks it's one of the better defragmenter.
Well you may try this alternative:
support.microsoft.com/en-us/kb/982736 caused the problem pertains on formatting the hard drive and suspected the system reserve partition.