Press Win + R keys to open the Run dialog box, and then type regedit in the box and hit Enter. To fix the problem, you can try deleting the affected CCleaner entries from Registry Editor. Remove the CCleaner Entry Keys from Registry EditorĬCleaner not opening Windows 10 can be caused by issues with the registry files of certain applications.

Now, you can restart Windows and check if the “CCleaner wont open” issue still persists. Step 3. Tick the checkbox next to Turn off Windows Defender Firewall (not recommended) for both private and public network settings. Step 2. Click on Turn Windows Defender Firewall on or off at the left side. Step 1. Type firewall in the search box and select Windows Defender Firewall from the best match. Here we take Windows Defender Firewall for example: In order to run this program smoothly, you can temporarily disable your third-party antivirus software like Avast and even Windows Defender. Disable Any Third-Party Antivirus Program and Windows Firewall TemporarilyĪccording to a survey, some certain antivirus software is one of the most common reasons why CCleaner won’t open Windows 10.

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