The avast self defense has nothing to do with this.
This is
not true, well at least for me.
Turning off Avast's
self-defense module (followed by a reboot) allowed successful completion of backups
using the Task Scheduler. Backups work fine with the
self-defense module active if they are run manually. The backup problem only occurs using the Task Scheduler.
My issue did not start until the next scheduled backup
after I upgraded to version 17.1.2286 (build 17.1.3394.42). I don't know if this self-defense module is a new feature, was turned on in the new release, or was upgraded.
Deactivate the self-defense module as described by member gtdurham or go to:
http://forum.macrium.com/FindPost10821.aspxI opened a support ticket with Macrium and they gave me the solution described in the post as well.
They also told me that
"We have reached out to Avast to work with them on a resolution but they, unfortunately, declined".
I'm completely disappointed that Avast chose not to work with them assuming that that statement is true (which I have no reason to believe otherwise).