Following the answer here:
How can I run a scheduled task as SYSTEM
I have created task to be run using SYSTEM accountTask to be run on System account
But it does not start on scheduled time.
When I change it from system to my account it runs without problems
Why? Is it because "Run only when user is logged on" option checked? ( on the scheduled time I am logged to computer ). But this option is greyed - I can not change it.