I will post here since I am having the same problem. Avast keeps finding a file in my app data temp files that is fpb.tmp. The scan reslut says "status: Error. System cannot find path specified". While I can choose an action, I am unable to highlight, by clicking the file name, or "apply" any actions.
I keep avast up to date, have run multiple full scans, ran malwarebytes, window's defender with no success. I am at a loss as to what is wrong.