I am running Windows XP SP2 with the Kaspersky 7.0 security suite and the Spycatcher anit-spyware program. Defraggler clashes with both security products which identify it as a root kit. (This, incidentally, seems to have prompted someone to report Defraggler as malware with McAfee SiteAdvisor) Even after "training" both Kaspersky and SpyCatcher to regard Defraggler as benign, my computer would still grind to halt with it present. I eventually had to temporarily disable Kaspersky just to run Defraggler's uninstaller. I realize Defraggler is still in beta but has anyone else run into this problem?
