I tried to launch TechToolPro 12.0.3 and it froze (spinning beachball). I uninstalled it, reinstalled it, and got nowhere. Micromat sent me a fresh installer but that didn't solve the problem. At Micromat's request, I sent them a system report. Within a minute, a lightbulb flashed in my mind: Restart!

Problem solved! This has solved issues with other apps (notably Microsoft AutoUpdate) and I should have thought of it first. Duh!!!

Just a thought and reminder to everyone...