I am still running CCleaner v6.39 because I had a terrible experience with CCleaner 7. I posted about that HERE.
I use the Registry scanner about once per week, and after uninstalling a program. It usually finds a few issues. I always select the option to back up the items that CCleaner has flagged before letting it delete those items from the Registry. Today I noticed that the last few .reg files it created were all 1KB in size. I opened the files in Notepad and discovered that there is nothing in them except the first line that says, “Windows Registry Editor Version 5.0”. None of the items it deleted were backed up. The last .reg backup file that has something in it is dated Jan 5, 2026. I have used CCleaner to scan and clean my Registry 5 times since that date, and all of those files .reg have nothing in them.
I am aware that there is a risk in using CCleaner, or any product that claims to clean the Windows Registry. Since it makes a .reg backup file of everything it is going to delete, I felt that the risk was acceptable because I can easily restore whatever it deleted. My error was assuming that CCleaner was actually saving the list of items to be deleted in the .reg backup file it creates. What could cause this, and how can I fix it?
You have to remember that v6.39 is no longer supported, and will stop working properly over time.
Still using v6.39 is only a stop-gap measure while you decide what alternative cleaner you are going to use in future.
(That might even be CCleaner7 if it ever improves enough to actually be usable).
In the meantime you should find this useful:
PS. To backup the entire Registry open regedit and right-click on ‘Computer’ then select ‘Export’
Thanks for your response. Yes, I know that v6.39 is no longer officially supported and CCleaner is pushing everyone to update to version 7.
I know how to back up the Windows Registry, but that process backs up the entire Registry. CCleaner generated a reg file that only contained the items it marked for deletion. I could back up those items manually, but sometimes the list is rather lengthy. I guess I could paste the list into a ChatGPT session and let it write a batch file to back up only those items. I will start looking for a CCleaner replacement. Thanks again.
Try checking, or unchecking i forget, hide warning messages (or something like that)
It sounds like you may have accidentally checked don’t show this again on a past reg clean
The registry cleaner is working as expected with my CCleaner Free Portable v6.39.11548.
As a test I ran my v6.39.11548 registry cleaner today to clean up one entry that was pointing to a Malwarebytes v5.4.6 installer I originally saved on my desktop, and after saving the cc_20260125_091821.reg file in the location I selected (i.e., in a folder I had previously created at C:\Users\<myusername>\Documents\PC Troubleshooting\CCleaner\Registry Backups) …
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Classes\Local Settings\Software\Microsoft\Windows\Shell\MuiCache]“C:\Users\ljmac\Desktop\mb5-setup-consumer-5.4.6.227-147.0.5453-1.0.106235.exe.FriendlyAppName”=“mb5-setup-consumer-5.4.6.227-147.0.5453-1.0.106235.exe”
After rolling back to CCleaner v6.39.11548 did you ensure Settings | Advanced | Show Prompt to Backup Registry Issues is ENABLED, and if so are you sure you’re looking in the correct folder you selected to save .reg files created by CCleaner v6.39.11548?
Thanks for your reply. Yes, “Show Prompt to backup registry issues” is checked, and the prompt does appear. Yes, the backup reg files are being saved in the location I specified. I just ran a Registry scan. CCleaner found 30 issues. I clicked “Review Selected Issues”, got the prompt to back up the registry, selected Yes, and watched the new backup file appear in the directory that I specified with the date and time stamp in the file name. The new backup reg file is 1KB. I opened it with VS Code and Notepad. It only contains 1 line that says “Windows Registry Editor Version 5.00”
The interesting thing is I did a reg scan and backup 2 days ago, and it properly backed up 79 items. The directory where I save these backup files is in a Dropbox folder. I thought it may have something to do with that. I have been saving CCleaner-generated reg backup files in this location since 2017 with no problems, but I did recently have a problem with the Dropbox updater that required me to manually uninstall Dropbox and then install the latest version. I just tried saving the reg backup file to a location that is not in Dropbox, but the new file was still empty. I also tried saving the backup file to a different physical drive - same problem.
It is possible that there is something on my system that is interfering with CCleaner’s reg file backup. Since it is working for you, and worked for me (once) 2 days ago, I will assume that CCleaner is not the problem and something else is interfering with the reg file backup process.
What is the current version and OS build number (e.g., version 22H2 / build 19045.6449) of your Windows OS? Open a Run dialog box (Windows key + R) and enter winver to find this information.
The January Patch Tuesday updates released on 13-Jan-2026 created a known issue where “some applications might become unresponsive or experience unexpected errors when opening files from or saving files to cloud-backed storage, such as OneDrive or Dropbox”. Microsoft released out-of-band (OOB) updates yesterday on 24-Jan-2026 for Win 11 25H2 / 24H2 (KB5078127: OS Builds 26200.7628 and 26100.7628) and Win 10 ESU v22H2 / 21H2 (KB5078129: OS Builds 19045.6812 and 19044.6812) to fix this cloud storage bug.
If you suspect your computer is affected by this bug please note that the release notes state that the OOB patches will only be delivered via Windows Update for Win 11 machines. Win 10 machines enrolled in the Extended Security Update (ESU) program must download the appropriate .msu standalone package for the OOB update from the Microsoft Update Catalog and install the patch manually or wait for the upcoming February 2026 Patch Tuesday of 10-Feb-2026.
