- Exclude the CCleaner app in Windows Security > Virus & threat protection > Manage settings > Add an exclusion, and retry opening it.
- Allow the CCleaner app manually in Windows Firewall from Control Panel > Windows Defender Firewall > Allow an app through Windows Firewall, and select CCleaner.
Basic Fixes
- Launch CCleaner as administrator : Right-click the CCleaner desktop shortcut and select ‘Run as administrator’. Alternatively, press the Windows key, search CCleaner, and click ‘Run as Administrator’.
- Run CCleaner from the installation directory : Press the Windows + E shortcut to open the File Explorer, paste ‘C:\Program Files\CCleaner’ in the address bar, and hit Enter. Double-click the CCleaner64.exe file to launch CCleaner.
- Update or reinstall CCleaner : Head to the Microsoft Store, search CCleaner, and click Update (if available). Alternatively, uninstall the app from Windows Settings > Apps > Installed apps, and install it afresh from the Microsoft Store.
Fix 1: Exclude CCleaner in Windows Security
CCleaner may not work properly on Windows 11 if the Windows Security app flags it as a potential threat. To fix it, exclude the CCleaner app manually in Windows Security settings and retry opening it.
Step 1: Press the Windows key, search Virus & threat protection , and click to open it.
Step 2: Click Manage settings under ‘Virus & threat protection settings’.
Step 3: Select Add or remove exclusions under the Exclusions section.
Step 4: Click Add an exclusion and select File from the subsequent menu.
Step 5: Navigate to the programs folder and double-click the CCleaner64.exe file to add and exclude CCleaner in the Windows Security app.
Fix 2: Permit CCleaner Through Windows Firewall
CCleaner needs internet access to check for app and driver updates. If the Windows Firewall blocks it, the app may not work as expected. To avoid the situation, permit the CCleaner app through the Windows 11 firewall.
Step 1: Press the Windows key, search ‘ Allow an app through Windows Firewall ‘, and click to open the associated Control Panel app setting.
Step 2: Click Change settings , approve the UAC prompt, select CCleaner from the list, and hit OK .
Fix 3: Tweak the Windows Registry
The 64-bit CCleaner version fails to launch or work properly on certain Windows 11 systems. If you’re experiencing it, delete some old registry associations and retry opening the app.
Note: Create a backup of your Windows 11 registry using File > Export, before making any changes.
Step 1: Press the Windows key, search regedit , and click Run as administrator .
Step 2: Approve the UAC prompt, paste the following path in the address bar, and hit Enter.
Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
Step 3: Right-click the CCleaner64.exe key and select Delete .
Step 4: Click Yes when prompted to confirm deletion and retry opening the CCleaner app.
