Turned of System Restore on my USB drive. Restarded Defraggler. Now I'm at 70% (for hours!) with 3 fragmented files (8% fragmentation).
This is horrible! I'm very, very, very disappointed now. Can I get a refund?
I'm experiencing the same problem. My 1 Tb USB HD had 6% fragmentation and 3 fragmented files. Defraggler is now on for about 20 hours and shows 12% fragmentation and 6 fragmented files at 75%.
I am (was?) very fond of Piriform's product (espec. CCleaner, Recuva) so I gave Defraggler a try. Even donated 20 bucks for it (I still think the people of Piriform deserve it...) But now I'm a bit disappointed.