SAME problem, but no scanner or audio file connection. It happens to me when I modify and save a .docx file and then also save the same file as a PDF. It saves the PDF the first time, but on the second try, can't rename, can't save, being held by Avast. Sometimes it is released with a reboot, sometimes it is not! And the Advast UI is blank. I think this problem has a large foundation and scanner, audio or whatever issues are nothing more than Red Herrings. The problem is Avast, period! Yes, I have the latest edition of Avast and this started with the most recent update on 6/26/2018.