It may be because the version 8.2 360 you are currently installing overrides the previous version 8. 1 360. You can look for the previously installed 360 folder, which is generally C: \ program files \ 360 \ 360 safe \ utils. There is a 360 security guard registry slimming program called RegClean.exe in utils, which you think doesn't exist. If it still doesn't exist here, it is probably already there.