I made this new account solely to report this issue, as it is serious. As you read this, I'm currently on a freshly installed copy of Windows 10. No, I'm not talking about a reset or a reinstall; I'm talking about a full-blown partition format to unallocated space, and then an installation. Luckily, I had another system to back up my files before doing so.
Normally, I wouldn't jump to conclusions and point fingers at any one program, but this time was special: I had nothing else running besides CCleaner, and I ran it right after I restarted the computer. My computer is lightly used; it has been malware/virus free for the past 10 years. It's primarily a production machine for Premiere Pro, and some light video gaming.
I run CCleaner maybe once every 3-4 months to clean up my computer. Yeah, not very often. Whenever I run it, I update it before doing any cleaning.
After it was updated, I did the usual analyze, and then I cleaned my computer. After that, I went to the registry cleaner and ran that with all options enabled. I cleaned all of the entries, and made a backup of the registry edits. After that, I reviewed some of the scheduled tasks, and then I went to the uninstaller feature, and uninstalled a few Windows Store apps that came bundled with Windows 10.
Once this was all done, I exited CCleaner, and attempted to use my computer like normal. I tried to open up the start menu, and then the issue began. My start menu wouldn't open. I tried pressing everything I knew; Ctrl + Alt + Delete, Windows + Run, etc. Everything else on the system worked fine. The start menu was the only thing that wasn't working.
Obviously, I decided to restart my computer. I pressed Ctrl + Alt + Delete to restart there, and an error message popped up that I've never seen before regarding something from the system that failed to run. I didn't really know what it meant, so I just clicked OK and then I restarted the computer from that screen.
After my computer reached the Windows 10 logo and had the spinning dots, it just hung there. Five minutes. Ten minutes. Twenty. It just wouldn't progress. The dots kept spinning, but that was it. I force restarted my computer with the button on my case, and it repeated the same thing; it just hung. At this point I realized, CCleaner bricked Windows 10.
I don't know how it did it, but it did. At this point in time, I had mixed feelings. I trusted Piriform since CCleaner has always been a great program, but I never thought a simple cleaner software could cause this to happen. Anyway, with no other means left, I loaded up my Windows 10 installation disc and I initiated a reset with my files intact. The process went through as expected, but after the installation restarted the computer to further progress with the installation, as Windows 10 started to boot with the dots, it gave me an error saying that it couldn't install Windows onto the computer hardware I had. What in the world?
I tried restarting again, but to no avail. With no other choice, I backed up my files by taking my hard drive out and connecting it to another computer, and then I proceeded to do a fresh installation through the setup. Some 20 minutes later, and I'm at the boot again, but this time, it just keeps restarting after showing the spinning dots for a while, and repeating that process. I then realized that not even this could save Windows. I needed to do a full-blown reformat.
So I did, and doing so finally allowed the installation to succeed. Here I am, describing everything I can remember that went on for upwards of five hours.
I don't have any logs to provide because well, I had to reformat the computer, but I hope that somebody from Piriform reads this and looks into their software for anything that could potentially cause Windows 10 to get bricked. It's definitely a serious issue, and I wouldn't want it to happen to anybody else. I know some basics of system recovery so I was able to get my system back up and running, but if an ordinary user were to experience this issue, they would probably be forced to consult some tech expert to get their system fixed, which would cost them quite a bit of money.
I know this isn't much information to work off of, but frankly I'm not sure there would be any to provide, with the system in that state. My computer was healthy and perfectly functional before I ran CCleaner. I'm using the free version of CCleaner.