thanks I managed to install again by changing the account.
I had same problem, tried most things but all failed. Did System Restore and that cleared it.
Bitdefender is plagues with increasing problems. If you are looking to have free AV and can clear the Bitdefender try 360 To…
Now have further problem. Bitdefender is no longer showing veriified in Mozilla Add Ons. Does this mean I am not protected.