Serious Issue: Latest CCleaner Can Brick Windows 10

CCleaner for Windows CCleaner Windows Bug Reporting
1
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.
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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.
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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.
2

It's messed up because you blindly ran the registry cleaning. Always (and this isn't just win10 it applys to every windows version EVER) run registry cleaning (ccleaner or competition) with care. Read my signature for a complete explaination on this.

As for a fix for the situation you got yourself into, I'll have to leave that to another forum member.

3

It's messed up because you blindly ran the registry cleaning. Always (and this isn't just win10 it applys to every windows version EVER) run registry cleaning (ccleaner or competition) with care. Read my signature for a complete explaination on this. As for a fix for the situation you got yourself into, I'll have to leave that to another forum member.

There are three issues with that "solution." First, you can't expect anyone to not simply run it with all settings enabled (which is likely default, and implies that it is safe). Second, not everyone knows what all the different kinds of entries are or mean. And third, even if you do individually clear entries, it only takes one bad entry to brick the system, and you wouldn't be able to do anything about it when it does happen.

This is a serious issue that needs to be addressed. A program like CCleaner, highly regarded and recommended by software experts for home and corporate users, should never even remotely have the potential to cause system failure. If it does, it means it is touching something it shouldn't, which is Piriform's fault for being careless.

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Sorry but I disagree.

If you blithely run a programme without knowing what it does / could do then that is your carelessness.

There are enough warnings on the internet about using registry cleaners - if you are not sure what you are doing

Reg cleaners have their place to do a specific job

If you use a tool to do the wrong job, or without knowing how to use it, then don't blame the manufacturer when it goes wrong.

(I cut my arm off with a chainsaw - they should not have let me use one).

I do agree that the reg cleaner included with CC should not be as prominent, and have said so in the past.

5

Registry cleaning especially in Windows 10 which is always receiving updates is a recipe for disaster.

6

for me, overriding all the above comments is the understated fact that regularly cleaning your registry is just not required.

personally I take it a step further and would say, not needed at all.

above average risk with little to no benefit.

7

I would not be so eager to blame CCleaner.

I've had similar symptoms in Windows 10 Home without running CCleaner.

What you describe can be the result of Windows Updates, hung Explorer, hung services, or who-knows-what.

I do NOT think CCleaner can be blamed without more evidence. I think it may be a coincidence.

My FINDING and RESOLUTION ...

The Windows logon failed to load because the logon service was blocked by some other service that failed to start (stuck in the 'starting' phase).

I used a different computer, launched Services.msc, remotely connected to the services on the hung computer, saw which service(s) were hung, figured out the name of the process, used pskill.exe to remotely kill the process, then the logon appeared.

I did not find a root cause, however Windows has worked fine since after some tweaking to services.

You can check your Windows Event Logs for services that fail to start and either set them to 'manual' (preferred) or disabled (careful).

8

I had the very same thing happen, and I think that the response is overly insensitive. To accuse the user of being irresponsible because Ccleaner destroyed the computer? There is an assumption that the components such as the registry cleaner, the basic cleaner, and the newer tune up are set for ultra conservative modes. The novice user selects the default mode because he does not want to chance making an error and then CCleaner ruins his operating system because of it? Sorry, but I'm not using Ccleaner ever again. It was too much work having to restore my computer after Ccleaner destroyed Windows 10. There is clearly problems with CCleaner. I know I would never run it again.

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@Figaro14

Yours is the first post that has been added to this thread for 3 years.

CCleaner doesn't destroy computers as far as I know. I've been using it for almost 15 years, however I don't use the registry cleaner now as Windows 10 doesn't need it (and this function may be hidden in a future update to CCleaner)

10

Registry cleaners always run the risk of breaking the operating system, always have and always will. Then there's also the issue with other things being updated so much that can break the operating system as well and it's not just limited to updates from Microsoft, other software makers can release buggy software or drivers that will wreck the operating system - been there and done that especially with Win98 and WinXP, but the issues still exists with Win10.

One thing for certain make regular disk image backups of the drives necessary for Windows to an external/portable disk drive that you unplug after making the backup. Try to have at the absolute minimum three known good backups, it will eventually save you allot of grief at some point. There's many good freeware tools that can disk image your system and have it up and running in minutes (especially if on an SSD) should a restore be required, and it will be as if nothing changed on the system based on the disk image date/time. Of course don't forget to periodically backup internal secondary disks/partitions too.