If you have any trouble with your Avast antivirus, something is not working as it should or it interferes with other programs, try clean installation of Avast.
Before you download and install Avast again, make sure you uninstall Avast with Avast uninstallation utility (sometimes referred as Avastclear.exe)
How to uninstall Avast
1. Download Avast uninstall utility from this link.
2. Open downloaded file (avastclear.exe)
3. You will be prompted to restart Windows in safe mode. Close all your programs and save your work. Confirm both dialogs with clicking on “Yes”
4. System will restart in safe mode and start Avast Uninstall Tool automatically. All information should be detected automatically. Make sure they are correct and hit uninstall.
5. Avast will now uninstall, wait for progress bar to finish.
6. Once you see confirmation (below), Avast was uninstalled from your PC. Hit “Restart computer” to reboot computer without safe mode.
7. Download Avast installer and proceed to installation if you wish to re-install Avast.