Installer deleted my files

CCleaner for Windows CCleaner Windows Bug Reporting
1

Your app just deleted half my apps after I ran the installer. A small window appeared, and after a while I noticed that some folders on the C: drive had disappeared. Then I noticed that a folder with custom utilities had been wiped out completely. So it deleted like 50 GB until I killed it in task manager. WTF??? I can’t use my PC anymore and have to reinstall the system and apps. I’m fcking devastated. I can’t even launch most of the apps that survived. I checked the installer with virustotal in case I downloaded the wrong version or anything, nah I downloaded the correct one from your website.

2

Hi @wongv,
I want to reassure you that the CCleaner installer is not designed to delete, wipe, or remove any files, folders, or applications from your PC. The installer’s sole purpose is to place the CCleaner application files onto your system, and it does not interact with or modify any existing data outside of that scope.

That said, we take reports like this very seriously and want to investigate this thoroughly. To help us look into what may have happened, could you let us know:

  • Did you use any functionality within the CCleaner app itself after the installation completed — for example, running a Health Check, Custom Clean, or the Software Updater? If so, which features did you use?

  • Were any automated or scheduled tasks configured in CCleaner prior to this incident?

  • Which version of CCleaner did you install, and what version of Windows are you running?

Any detail you can provide will be a great help in our investigation.

3

So I ran out of space on my C: drive and launched Space Sniffer to see what was taking up the space (I do this routinely in such cases). I didn’t find anything to delete, so I decided to download CCleaner, thinking it might help delete caches, temp files, etc. I ran the disk cleanup utility and freed up a couple of GBs.

Then I launched CCleaner installer, and it got stuck in the small window that appears right after launch. After maybe 5–10 seconds, I noticed that some folders had been deleted, like C:\inetpub left over from a Windows update, and others. Free space went up to 10 GB. I opened Task Manager to kill the process, and free space jumped to 60 GB. I then found out that some apps had been deleted, like Visual Studio Pro, OBS Studio, and others. I couldn’t launch MSI Afterburner, LibreOffice, and some others.

I thought I might have accidentally pressed Delete in Space Sniffer or something, but it doesn’t even have that functionality. I rarely install new software and always check it with VirusTotal, so the only obvious suspect is CCleaner. The last apps I installed were a K-Lite Codec Pack update a week ago, and Happ and Amnezia VPNs downloaded from GitHub two weeks ago, everything else was installed months ago.

  1. I killed the installer, launched it again and installed. Ran the app, didn’t use anything, just closed right away.

  2. No I don’t think so.

3.1 CCleaner version: I don’t know. I downloaded the latest file: ccsetup_online_setup.exe (1,749,176 bytes).

3.2 Windows version: Windows 11 Pro 25H2 26200.8328.

4

Thank you for these details.
Please could you navigate to the location below in File Manager and zip up all files in that folder.
C:\ProgramData\Piriform\Icarus\Logs
I have sent you a DM to request that you send the log files there.
If you have any issues, please let me know.