have the program Registry Mechanic installed on the PC?
If so, it seems defrag is looking for a file that is part of that.
If you have Registry Mechanic but no longer use it, uninstall it, then reboot, then try defrag.
If you no longer have it, download and install a registry cleaner, (CCleaner is ok), and run it to fix any registry issues. Reboot, then try defrag again.
I hope that helps.
When I run defrag, it gets to about 10% then stops on something called " MOVING FILE-REGISTRY MECHANIC SOFTWARE " and goes no further. I cant find this file on my PC. Any help please?