Quote:
Fix automatically (default): attempts to repair the file. If unsuccessful, moves the file to the Virus Chest or deletes the file if neither action is successful
So, if the 4 unimmunized hosts file entries are due to Avast, it could be possible that Avast is able to fix it automatically, therefore nothing shows in the Virus Chest. You should get a notification if that happens, though. So could you open the Actions screen and check to see that "Show a notification window when action is taken: notifies you each time an action is applied by the Shield." is ticked? From the looks of it, you might have to check under each detection type: Virus, PUP or Suspicious