The reason why some files cannot be defragmented by the windows defragger is usually (1) fragmented system files such as the master file table (MFT) or paging file (PF), (2) lack of sufficient disk space, or (3) a combination of the two. The windows defragger requires > 15% free space to defrag. Also, it is unable to move/defragment the MFT and PF despite the fact that support for MFT movement is actually built into the defrag API. Only advanced commercial defragmenters such as Diskeeper 2008 (non-freeware) can defrag the MFT, and newer DK versions don't even require a boot-time defrag fo
