This issue can be caused by conflicts with the configuration of Windows services. This is really annoying … what prevents the entire program from running. Sometimes Avast Cleanup Premium or Avast Antivirus reports that the user interface could not be loaded. Update: Stop getting error messages and slow down your system with our optimization tool. A quick guide to troubleshooting a faulty user interface:.What does it mean when Avast reports it failed to load the user interface?.