"Error opening file for writing" is very common during install, see the solution in this topic:
https://forum.piriform.com/topic/5739-solution-when-ccleaner-wont-install-or-download-windows/
"Error opening file for writing" is very common during install, see the solution in this topic:
https://forum.piriform.com/topic/5739-solution-when-ccleaner-wont-install-or-download-windows/