I have accidentally discovered CCleaner removes registry entries required by Iolo System Mechanic Pro to work normally. More specifically Iolo Antivirus can not start automatically when booting up and you are presented with error messages when you try to start the program manually and enable realtime protection. I have Iolo System Mechanic Pro installed on several PCs and have had this same issue on one PC for quite some time. It wasn't until I ran CCleaner on my laptop today and started receiving the same error that I realized CCleaner removed registry files required by Iolo System Mechanic Pro. I always save a backup copy of the registry files deleted by CCleaner. I restored the deleted registry files in order to fix the problem. Now I need help determining exactly which registry files deleted by CCleaner need to remain in the registry for Iolo System Mechanic Pro to work normally.