I scheduled a task to perform a windows backup of a single disk on the my server.  When I tested it, the task ran successfully – no problems, no errors; just as I expected. 

However, when the task ran as scheduled, it failed with error value 2147943645.  I wondered was this the answer to life, the universe and everything in it?  No.  That is 42. 

After doing some research and reviewing the task configuration, I realize that the task will only run if the user of logged on:

So, this was the answer!!  I have to configure the task to run whether the user is logged or not.  Or, else I’ll get that nasty error value.