I know this is a First Defense ISR forum, but I hope that it is within reason to post a Perfect Disk issue. The issue is as follows: The issue arrises consistently when an Offline Defrag. is attempted. The Offline Defrag Settings set as follows: http://dustinallen.com/Wilders/PerfectDisk.JPG I select Defragment > Offline Defragment and as usual I get the message asking if I want to perform the Offline Defrag during the next reboot. I say yes, then reboot. Here is what happens (This may not be exact because the message is not up long enough for me to get word-for-word): Drive Not Dirty Perfect Disk could not gain exclusive access to C: Drive. There is a possible driver conflict... There is more, but I wanted to see if anyone has any idea what may be causing this.