I'm a registered user and have reported issues with Tech Tool since installing version 4 some 12 months ago. The tool looks good on the surface, sports many features... but it us absolutely useless. The disk optimizer and defrag feature corrupted my harddrive and only Disk Warrior, which I purchased due to that incident, was able to bring my files back. I have since tried the optimizing and defrag feature again, but I'm not happy with it: it's very slow, and potentially harmful. I also wrote various times to Tech Support that merely reporting about the existence if a corrupted file is not what I expect from a repair tool. Tech Tool states that there is no way to fix a corrupted file, however, it also does nothing to delete it (or give the user an option to do so). On one occasion I had an invisible info.plist file in the preferences folder... know how many there are??? How difficult it is to find the corrupted one yourself???

To sum up: Tech Tool 4 was a waste of money. Updates are sporadic and I have since switched to Disk Warrior and iDefrag. Great tools that not only claim to do the job, but get it done. Better. Faster, Safer.