Ran Custom Clean three times, each said must close Firefox, I did, then did not clean any. Same in Health Check, says Firefox still running, I say YES to close. Shut down rebooted still will not clean. Will look at similar ones to my topic also.
James82 over and out
if you use the ESET security program that could be interfering with ccleaner’s closing firefox, and so the firefox-files are not being removed.
see this post:
https://community.ccleaner.com/t/ccleaner-6-37-11523-and-older-does-not-delete-any-files-or-cookies-firefox-140-x-x-solved/154116/13
you need to make sure that the ESET security program is not blocking ccleaner from closing firefox.
if you close firefox before running ccleaner then it shouldn’t be necessary for ccleaner to close it. so, i would suggest you close firefox before running ccleaner.
as far as i can tell, firefox does not normally run in the background after you close it. i don’t see any settings that would cause it either to run in the background or to not run in the background.
“malwarebytes browser guard” does not prevent a browser from being closed (unlike ESET’s “browser guard” ). it simply blocks malicious URLs and IP addresses, to help to prevent malware-infections.
Hi James82:
Firefox is my default browser and I use the Microsoft Defender antivirus built in to my Win 10 OS, supplemented by Malwarebytes Premium anti-malware’s real-time protection. I don’t normally allow CCleaner to clean my Firefox browser (I have Firefox configured to clean most of my browsing history on exit - see my aside*** below) but I closed my Firefox browser and ran a Custom Clean with CCleaner Free Portable 6.38 today with a few Firefox items selected for cleaning, and CCleaner was able to clean my Firefox browser correctly.
As suggested by redwolfe_98, did you check to see if the ESET Browser Protection feature that was described in Fox_Mulder1’s 05-Jul-2025 post in their topic
CCleaner 6.37.11523 and older does not delete any files or cookies Firefox 140.x.x [SOLVED] is the cause of your problem? Fox_Mulder1 provided instructions <here> in their 08-Jul-2025 post that describes how they created an exception for the CCleaner executable (e.g., C:\Program Files\CCleaner\CCleaner64.exe or wherever your CCleaner Professional executable is located on your system) in the list of allowed files for their Browser Protection settings in ESET Internet Security. See [KB5657] Activate and configure ESET Safe Banking & Browsing for more information about Browser Protection.
Do you have a standalone subscription for ESET NOD32 or is it part of one of the ESET Home Security products described in [KB8510] ESET NOD32 Antivirus? I’ve never used an ESET antivirus, but according the product comparison chart at https://www.eset.com/ca/home/antivirus/ (you must click the “What’s inside” link to see the full feature list) your basic ESET NOD32 antivirus does not include the Safe Banking or Safe Browsing features that are included with Fox_Mulder1’s ESET Internet Security so I doubt your Browser Protection settings, if any even exist in your ESET NOD32, are identical to what Fox_Mulder1 described for ESET Internet Security.
Perhaps the best way to test if your ESET NOD32 antivirus is conflicting with CCleaner is to temporarily disable your ESET NOD32 real-time protection [i.e., right-click the ESET icon in the system tray, select “Pause Antivirus and anti-spyware protection”, choose the desired time duration (e.g., 10 minutes, 1 hour, until reboot) and click “Apply” as described in [KB548] Disable protection in ESET Windows home products]. Then close your Firefox browser and run a Custom Clean in CCleaner to see if it cleans your Firefox browser. If that works and your ESET NOD32 antivirus doesn’t include any kind of Browser Protection you might have to add a process exclusion for CCleaner64.exe in your advanced ESET settings as described in the ESET NOD32 online user guide.
Just FYI, my Firefox setting at General | Startup | Open Firefox Automatically When Your Computer Starts Up is DISABLED, and my automatic background updating at General | Firefox Updates | Allow Firefox To | Automatically Install Updates | When Firefox Is Not Running is also DISABLED as shown below. When I close my Firefox browser there are no instances of firefox.exe running in Task Manager.
*** ASIDE: I stopped using CCleaner to clean my Firefox browser in 2020 after a bug in an older version of CCleaner incorrectly erased all custom settings in NoScript and many other Firefox browser extensions - see circcc’s July 2020 topic Problem with Firefox 79 [fixed in v5.70]. I also feel that some of the Firefox cleaning by recommended by CCleaner is too aggressive - for example, see my 22-Nov-2022 post in aboriqua’s Firefox bookmarks backup? about how CCleaner started cleaning my Firefox bookmark backups without my permission.
I believe it’s much safer to use Firefox’s built-in browser history cleaning (e.g., Settings | Privacy & Security | Browser Privacy | History | Clear History When Firefox Closes | Settings) to clear my browsing history when I exit Firefox and I normally don’t let CCleaner touch this browser. See the Mozilla support article Delete browsing, search and download history on Firefox for more information.
Dell Inspiron 15 5584 * 64-bit Win 10 Pro v22H2 build 19045.6093 * Firefox v141.0.3 * Microsoft Defender v4.18.25070.5-1.1.25070.4 * Malwarebytes Premium v5.3.6.205-138.0.5346 * Macrium Reflect Free v8.0.7783 * CCleaner Free Portable 6.38.11537