"Error starting the product update. Scheduler has not been started."In my case, the fix was easy. I went to the directory with the antivirus executables
C:\Program Files\Avira\AntiVir Desktopand right-clicked the program
update.exeand chose "run as administrator". It started to work and the program was updated within a minute. Next time, the update already works via the menus just like you expect. The problem is due to some administrator right glitches: we probably tried to start these processes without the required privileges.