Downloaded latest update 48 but when trying to install it just returns to previous version 24.
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; <span><a href="https://www.piriform.com/ccleaner/builds" rel="external nofollow">https://www.piriform.com/ccleaner/builds</a></span> (or use FileHippo for previous versions)
reboot the PC then install CC from your downloaded file.
if you need to convert this Free version to the Pro, go to Options > About and enter your license key.</p>
if no luck, try the install with the PC in Safe Mode.
or try the Slim or Portable builds to see if they work.</p>
If the above doesn't work also see this post by Stephen, and follow the link in the post to see if it fixes the issue.