it could be an issue with installing over-the-top...
try this;
uninstall your current version first.
then go into the Program Files folder for CC and delete its contents
(keep the .ini file if you have customised settings)
download the latest build from here; <a href="https://www.piriform.com/ccleaner/builds" rel="external nofollow">https://www.piriform.com/ccleaner/builds</a> (or use FileHippo for previous versions)
reboot the PC then install CC from your downloaded file.
if you had the Pro version, to convert this Free version to the Pro, go to Options > About and enter your license key.
if no luck, try the install with the PC in Safe Mode.
and try the Slim or Portable builds to see if they work.