Cannot defrag drive because it is locked by a disk utility.
Question
Cannot defrag drive because it is locked by a disk utility.
Cause
This issue is caused when other programs or files are being accessed in the background as defrag is being ran. If defrag detects any file change while being ran it will restart.
Answer
To resolve this issue make sure all open programs are closed and close all background programs. If doing this does not resolve your issue you can also run defrag through Safe Mode.