no idle standby after automatic backup

[Gary]

I schedule my PC to wake for an automatic backup at 1am. It does so
properly, but then does not automatically return to standby mode
afterward (although the monitor properly turns off). Without
intervention, it remains turned-on indefinitely. However, if I then
merely jiggle the mouse (which turns on the monitor, revealing the
Welcome screen), then the computer does soon automatically enter
standby mode after the appropriate idle interval. Automatic standby
when idle works under all other circumstances; it's only after waking
up for a scheduled backup that standby doesn't engage after the idle
interval.

Perhaps what's happening is that 1) automatic standby occurs when the
idle timer makes the TRANSITION to the specified interval; 2) the
scheduled backup does not reset the idle timer; 3) therefore, the
timer remains way PAST the specified interval, so the triggering
transition doesn't occur. But if i move the mouse, the idle timer gets
reset, and then the trigger occurs properly after the appropriate idle
interval.

If that theory is right, then I could work around the problem if there
were a way to automatically cause the idle timer to reset after the
backup. Apparently, though, a scheduled task (for which the PC wakes
up) does not reset the idle timer. Is there any way around this
problem?

Power scheme details: for all users (and for the default user, via the
registry) the screen saver (default XP saver) is set to engage after 9
minutes (with Welcome screen upon resumption); monitor shutoff after
10 minutes; disk turnoff after 20 minutes; standby after 15 minutes.
Windows XP Pro SP2, all updates installed.

 

[Gary]

I found a workaround. I schedule a task to run (if the PC is awake and
idle) after the automatic backup:
rundll32.exe powrprof.dll,SetSuspendState .
That puts the PC back in standby mode. Subsequently, when I reawaken
the PC, idle-time standby works too.