I kept noticing my wife’s laptop was not doing it’s scheduled scan at 2am on Sunday. I did a little more research and found that by default MSE does not attempt to wake a sleeping PC/laptop to do the scheduled scan.

To fix this you need to go into the control panel and open up the Task Scheduler. Then select “Advanced” from the pull down menu and then select “View Hidden Tasks”.

From there you should see a task named “MP Scheduled Scan”. If you select the properties you’ll see a settings tab. In the settings tab you’ll see a power management box. You should check:
“wake the computer to run the task”
and
“stop this task if battery mode begins”

This works for Windows XP. In my opinion it’s an oversight.

As far as Windows 7 and Vista. I know my main PC does not seem to wake at 2am on Sunday to scan the PC. I can not find the task, hidden or otherwise shown, for MSE. This could also be an oversight on Microsoft’s part.

So in the case of Windows & and Vista, you might have to manually add a scheduled task by using the MpCmdRun.exe command and setting it to wake the PC.

“MpCmdRun.exe -Scan” is the correct syntax.

Update: I did a bit more digging in Windows 7/Vista and found the hidden task for MSE!

It can be found by launching “taskschd.msc” from the start menu. You then expand “Task Scheduler Library” to find “Microsoft”. From there you will see “Microsoft Antimalware” and then “MP Scheduled Scan”.

Under the properties select the “Conditions” tab. Under the “Power” section check:

“Stop if the computer switches to battery power.”
and
“Wake the computer to run this task”

For the life of me, I do not know why these options are not default”

Lots of good info here:
http://www.thewindowsclub.com/command-line-utility-for-microsoft-security-essentials