Assuming you are running the Windows defragger, unfortunately, particularly with a badly fragmented hard drive, it doesn't always do a complete defragmentation in one pass. (I've seen it take as many as 3 passes for that defragger to completely defrag a drive.) In addition, that defragger will not defrag the page file.
To get a complete defragmentation, you have to use a 3rd party defragger like Diskeeper or some such.
Also any open files (such as Windows itself) will prevent the disk from fully defragmenting.
===========
Your hard disk drive could not be defragged because there might be a problem with some sectors of the drive. It would be better if you will run the checkdisk utility first before performing the hard disk drive defragmentation.
Last Wiki Answer Submitted: February 1, 2012 8:37 am by Denny Cherry64,550 pts.
If you live outside the United States, by submitting your email address you consent to having your personal data transferred to and processed in the United States.