%USER%\AppData\Local\Temp I ran the latest version of CCleaner and it did not touch this folder. I then manually deleted nearly 3GB of files from there. There are usually a few files that files that will not delete like: FXSAPIDebugLogFile.txt or ~DF285.tmp. The second file name is random but alway begins with the tilde. Though the folder may contain several usually only a few will not dump. Depends on what is running in the background.