I am using CCleaner Pro v5.41.6446, 64 bit on a Win 10/Pro 64 bit machine, current updates. I recently noticed that after running CCleaner, the history for Firefox is not completely cleared.
I am using Firefox Quantum v59.0.2, 64 bit. To clear the history, I still, after running CCleaner, have to go into Firefox >Library>History>Clear Recent History to completely clear the history.
I have all the check-boxes checked in CCleaner (App) Firefox except "compact databases".
Update: I went in to Firefox and cleared all history in Firefox. CCleaner is now cleaning Firefox. I am not sure what the issue was.
When I first ran CCleaner, it skipped over all Firefox components, even with the Firefox closed. After clearing history in Firefox, CCleaner is working as expected.