I installed this software and within two or three hours my system hung, which has never occurred before. And I mean HUNG! Everything froze, and after some fiddling around, i.e. try to run Force Quit, the cursor disappeared. This problem sprung up after I heard some very repetitive, but soft, disk sound which kept up, i.e. never stopped. As soon as I started investigating this by bringing up Activity Monitor and Force Quit, the system froze. FTR, I was able to see in AM that half of my 8 GB of RAM was in use just before this freeze, so I wasn't overtaxing the system.
Tried pushing the power/eject button (this is on a Mac Book Pro running OS X 10.6.8), and a fairly standard-looking query window me up asking me if I wanted to restart, shutdown, etc., but before I could even choose an option, the screen went dark/black and the spinning beach ball of death appeared (so I guess the "cursor" came back, sort of). I then attempted to do a hard shutdown again with the power/eject button (holding it down for 4 seconds and then a second time for 10 seconds) and after reading up on the matter, I also tried CMD+CNTRL+EJECT/POWER, which also did nothing. Even shutting the laptop would not put it into sleep mode.
After about 45 minutes while looking for help online on another computer and unplugging and replugging, I tried the power/eject button again and mercifully the machine shut down.
I then restarted it and things appeared ok. The first thing I did was attempt to uninstall OS Track; however, since I had it set up for starting on login, I wasn't able to quit it. All I could do was toggle off this feature and then reboot my machine once again. After which I yanked this app off my system ASAP.
I've had my MPB for 15 months and it has been very stable. Never had anything like this happen, so I strongly suspect it was this code. I acknowledge that I had three browsers (Safari, Camino and FireFox) with multiple tabs going at the time, but as I said I was still using less than half of my RAM.
Most of my ratings are self-explanatory; however, I also give it a low Ease of Use rating because of the way one must get out of it if it is set up to start at login, i.e. you must toggle this option and then reboot.
This experience also makes me that much more leary of downloading from the MAS.