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...
macOS 10.15.6, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P600, Photoshop CC, Lightroom CC, MS Office 365