tracking files not cleaned, Files coming back [Solved/Explained]

After performing a clean, there are often tracking files left. Only on a few occasions they are all cleaned.

Even cleaning several times in a row doesn't solve the problem. This issue exits for a while in different versions of CCleaner, always expecting that this would be solved in the newest update.

This post got scrambled during the Forum migration so has been re-written and posted as it’s own thread/

See: Files that keep coming back after cleaning - Explained