Could be files that are open - the built-in defragmenter can have issues
with that. Try booting into Safe Mode and defragmenting from there.
- Greg/Raxco Software
Microsoft MVP - Windows File System
Disclaimer: I work for Raxco Software, the maker of PerfectDisk - a
commercial defrag utility, as a systems engineer in the support department.
Want to email me? Delete ntloader.