Task Scheduler - tasks waiting for specified idle time don't start

Bobbob · 07 May 2013

I am baffled as to why tasks I create, about half the time, do not run if the system is not idle at their set time to run. As an example, I have a task to run Malwarebytes at 12:00 am every day. If the system is idle at that time, the task starts and completes successfully. If the system is not idle at that time, sometimes it will start and complete sucessfully once the system has been idle long enough but sometimes I just get a "Task trigerred on scheduler" in the history and it never does run for that day. The same thing happens for all tasks I set up. Here are the settings for the tasks:
General:
Run only when user is logged on (changing to "Run whether user is logged on or not doesn't help)
Run with highest privileges checked (unchecking doesn't help)
Configure for: Windows 7, Windows Server 2008 R2 (I'm on Windows 7 - changing this value to one of the other selections doesn't help)
Triggers:
At whatever time every day
Actions:
Start whatever program
Conditions:
Start the task only if the computer is idle for: 10 minutes
Wait for idle for: 10 hours (changing to "Do not wait", 1 minute, 5 minutes doesn't help)
Wake the computer to run this task checked (this is a desktop and I have all hibernation, sleep shut off)
Settings:
Allow task to be run on demand checked
Run task as soon as possible after a scheduled start is missed checked

The weird thing is I found that MS has a task out there for System Restore which is set up just like my tasks (scheduled for every day at 12:00 am with the same conditions and settings) and it always works. For example, last night at midnight I was on my PC so it wasn't idle at the 12:00 am start time for both tasks. I got off the PC around 1:00 am. History for MS's Sytem Restore task shows it started at 1:29 am and completed successfully (which is what I would expect to happen). My Malwarebytes task history shows "task triggered on scheduler" at 12:00 am but it, for some reason, never went ahead and ran (as the System Restore task did) while I was off the PC between 1:00 am and returning around 8:00 am. This happens about half the time my PC isn't idle when one of my tasks is set to run. I have another task to run a registry backup porgram with two triggers - one at 3:00 am and one at 3:00 pm. It does the same thing for both triggers. Whenever the PC isn't idle when the trigger time is hit (whether 3:00 am or 3:00 pm) sometimes the task will run once the PC is idle long enough and sometimes it doesn't.

This behavior makes the scheduler pretty much worthless to me if I can't trust it to do what I need it to do. I've seen other people describing similar situations where the task doesn't run later if the system isn't idle at the scheduled time but I've seen no solution so I'm trying again.

I think sometimes this is a problem because people think their systems are idle but they're not. I know I've had services and one time that Conduit crapware that got installed without asking that used 3 or 4% and more of the CPU constantly. But, I have Drivegleam running (which I love) and I can easily see when my system should be considered idle based on CPU usage and physical disk activity.

Any insight would be greatly appreciated. Or, at least, thanks for letting me whine/vent here.

Bobbob · 14 May 2013

Hmmm ... well, just in case there is any interest in this situation, here's what I've determined (or maybe everyone else has already figured this out):

First, I determined that missed tasks were not being run whenever the system was restarted after a task was triggered but still waiting for idle condition to run. So, if I was on the PC when a task was supposed to run, once I got off the PC (without logging off), the task would then run after it determined the idle condition. But, if I was on the PC when the task was supposed to run and while it was still waiting for an idle condition, did a system restart, the task was never triggered again.

The easy workaround was to change the tasks to use user account System which forces "Run whether user is logged on or not". When this is done, the task gets re-triggered after a system restart and eventually runs once the idle condition is determined. However, that didn't work for my Malwarebytes task because I only have the free version which does not command run in silent mode - it prompts me. Tasks that are interactive can only be run as "Run only when user is logged on" - and that can't be done for user System. So, for that task, I have it set to use my user account and "Run only when user is logged on" and added a trigger "At log on" for my user account. That way, if I do a restart after the task is triggered and before an idle condition is determined (which normally then means the task gets forever lost), the task gets re-triggered upon the logon. Of course, this means that, depending on the time the task last got to run and when I restart the PC, that the task may run again when I don't really need it to but the task does always gets run at least once a day as I want.

I don't know if this not re-triggering a missed task after a restart when the user account is not System is a bug or a particular problem of my system. However, I had to do a repair install at one point to get WMP working (first time I ever had to do any kind of system re-install to fix a problem since using the original Windows OS) and this missed task problem existed before and still after the re-install (it did fix WMP, however, after turning the feature on and off with reboots, etc. didn't). I saw posts regarding this matter saying the problem was that a non-System user's credentials get lost after a system restart. Well, that makes sense to me that they would. It doesn't make sense to me that the credentials wouldn't be re-established by the time the "Run only when user is logged on" trigger is met. It seems to me the problem is simply that, for whatever reason, triggering via logon (at least after a restart) doesn't cause the task scheduler to pick up previously triggered tasks that never got to run as it apparently does correctly after a restart when the user account is System or because the trigger in that circumstance is upon system restart rather than user logon. I would be interested in knowing if anyone else has noticed whether or not their Windows 7 re-triggers missed tasks after a restart when user account is not System. Thanks.