How to Fix CCleaner Problems on Windows 11

Running CCleaner in Compatibility Mode on Windows 11

If you’ve been trying to run CCleaner on Windows 11 and it’s behaving oddly — like refusing to open or crashing randomly — you’re not alone. It looks like this popular cleaning tool isn’t fully optimised for the latest Windows version. Usually, running it as an administrator, making sure it’s up to date, or adjusting permissions helps resolve most issues. But if those steps don’t do the trick, here’s what finally worked for me: running CCleaner in compatibility mode.

How I Got CCleaner to Launch in Compatibility Mode

Older programs like CCleaner can sometimes have trouble with Windows 11’s newer architecture. Compatibility mode tricks Windows into pretending it’s a bit older — like Windows 10 or even Windows 7 — and that often fixes launch glitches or interface hiccups. Here’s how I set it up:

1. Locate the CCleaner executable

   • Press Windows key + E to open File Explorer.
   • Navigate to: C:\Program Files\CCleaner. If it’s not there, check C:\Program Files (x86)\CCleaner.
   • Look for CCleaner64.exe. That’s the main file I used. On my older ASUS laptop, it was buried in Advanced menu options, so don’t hesitate to dig around if you don’t see it right away.

2. Open the properties of CCleaner

   • Right-click CCleaner64.exe and select Properties. Or highlight the file and press ALT + Enter.

3. Set it to run in compatibility mode

   • Switch to the Compatibility tab. Sometimes this isn’t immediately obvious — just click through the options, it might be buried.
   • Check the box for “Run this program in compatibility mode for:” and choose, for example, Windows 10 or Windows 8 from the dropdown list. The options will usually include a few older versions of Windows.
   • To help it run smoothly, also check Run this program as an administrator. Windows security can be a bit overprotective, especially with older or unsigned apps.

4. Apply the settings and test it out

   • Click Apply>, then OK. Sometimes, restarting Windows Explorer (Ctrl + Shift + Esc, find Windows Explorer in the Processes tab, then right-click and select ‘Restart’) helps the changes kick in.
   • After that, try launching CCleaner the usual way — double-click or right-click and pick Run as administrator. For me, doing that last step was sometimes necessary if it still wouldn’t open normally.

Why Compatibility Mode Makes a Difference

Honestly, it’s surprising how many older apps choke on Windows 11 — probably because they weren’t built for the new architecture or because security features are tighter now. Compatibility mode makes Windows pretend you’re running an earlier version—like Windows 10—instead. It’s like telling Windows, “Hey, everything’s normal here.” This trick fixed my launch issues and some strange UI glitches I hadn’t expected. Definitely worth trying before giving up.

Extra Step: Whitelisting CCleaner in Windows Security

If problems persist, it might be due to Windows Defender or other security software flagging CCleaner — especially if it’s an older or unsigned version. To stop Windows from blocking it:

1. Open the Start menu and type “Virus & threat protection,” then press Enter.
2. Click on Manage settings.
3. Scroll down to Exclusions and select Add or remove exclusions.
4. Click Add an exclusion and choose File.
5. Paste the full path to CCleaner64.exe. For me, that was C:\Program Files\CCleaner\CCleaner64.exe.
6. Double-click or press Enter to add it. This should tell Windows Security to ignore CCleaner during scans, reducing false alarms or accidental interference, especially if security software is blocking it unexpectedly.

This step made a big difference in my experience, because Windows Security can be quite cautious about older or unsigned apps, which can complicate troubleshooting.

Why These Fixes Matter

Overall, running CCleaner in compatibility mode and adding it to Windows Security’s whitelist can save a lot of hassle. Windows 11’s security and compatibility layers are now more strict, and many old apps can get caught in the crossfire. It’s frustrating because older software should still work fine, but Windows doesn’t always make it easy. These tweaks helped me avoid more headaches during a late-night fix-up — hopefully, they’ll do the same for you.

I hope this helps. It was tricky to figure out at first, but once I understood compatibility mode and security exclusions, CCleaner finally played nice. Double-check your Windows version, make sure CCleaner’s up to date, and verify the file paths and permissions. Sometimes, a quick reboot or running as admin makes all the difference. Windows can be a pain at times, but with patience, most problems can be sorted. Good luck — and hopefully, this saves you a weekend or two of frustration!