Cool Espresso, I put the service sched.exe in 'Manual', in my Services/Avira AntiVir Scheduler. And then: restart of computer (for put off your sched.exe, easy and safe). That's all.
And then, when I want (once a day ...):
* Services/Avira AntiVir Scheduler/right click: Start. And then
* Right click on Avira icon in the System Tray: Start Update.
* After Update: restart your PC.
Thank you for Espresso idea!
PS. I have the link of Sevices on my Desktop, of course. Allways.