Hi, sorry for the clean log button, it really has problems. Unfortunately, for the log files to be deleted you have to stop all avast serviceses and processes. Which means:
1. disable self-defence
2. net stop "avast! Antivirus"
3. net stop "avast! Firewall"
4. taskkil /F /IM "avastui.exe"
now you can delete the files, the start avastui from avast installation folder, and click the FIX NOW button.