Bitdefender compatibility

Ever since switching from Avast to Bitdefender for protection

CCCleaner has stopped running when I attempt to launch.

Is this a known anti-virus block? Is it likely old Avast startup

files are "fighting" the new Bitdefender?

How did you uninstall Avast?

Did you try using the cleanup tool afterwards?

https://www.avast.com/en-gb/uninstall-utility

(note you have to run it in safe mode.)

Did you white list ccleaner in bitdefender? What version of ccleaner?