I tried upgrading to the FREE version of this software but Windows would not allow to update & upgrade this version. Is there any solution to the problem?
what build of Win10 are you on?
can you provide a screenshot of the error message.
make sure you get CC from here; https://www.piriform.com/ccleaner/builds
if the normal build doesn't work, try the Slim or Portable.
when installing, don't change the name of the downloaded .exe file.