CEB1970

Actually, no. I would have expected issues during the beta but I very much doubt that there have been any major changes to Windows 10 since the last few release candidates. I use a lot of different software and this is the only program that has had any issue whatsoever, and a pretty serious issue at that (capable of crashing the whole computer). Does it surprise me that there are issues? Not really, particularly with a free program. But did I expect issues? No, and certainly not a system crashing one.

Same for me. I upgraded to Windows 10 yesterday (upgrade from WIndows 8.1, not a fresh install). From Task Manager Performance monitor I could see the memory suddenly shoot from 2.8GB (of 8GB) up to 7GB, then I would get a message asking to close CCleaner (or it would already be closed automatically). On a couple of occasions it crashed my computer and left it with a black screen and I'd get clicking/chirping feedback when I tapped the shift key (no other key would do anything). This happened with the version of CCleaner I had before the upgrade (which was a couple weeks old) and also with the latest version which I downloaded to try and resolve this. Since uninstalling CCleaner my system has been 100% stable. System is a Samsung with Intel Core i7-4500U @ 1.8GHz 2.4GHz, 8GB RAM, 64-bit OS. By the way, I should add that this behavior happened when I was NOT actively using CCleaner. It seemed to occur as CCleaner was reviewing potentially wasted space in the background. At least once (and I think multiple times), CCleaner popped up a message about space it could save me immediately after the massive spike in RAM usage. I was able to use CCleaner to successfully clean my registry after the upgrade, though :-)