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I configured the Windows 7 disk defrag utility to run on the 1st of the month at 1:00 AM. The associated task gets created in the Task Scheduler and all is well until the next time I reboot my computer. Once I try to go into Task Scheduler after a reboot, I get the following message:

The selected task "{0}" no longer exists. To see the current tasks, click Refresh.

After clicking OK and browsing through the folders under Task Scheduler Library to try and narrow which task is corrupt, I always get the same message when opening Microsoft > Windows > Defrag. After clicking OK again, I can see the content of the folder is empty.

It seems as though the task is getting deleted, but some sort of pointer or reference to the task is still existing (causing the error to be thrown). I've had this behavior happen on three separate machines all running Windows 7 Ultimate SP1 with all available updates installed.

Has anyone seen or can anyone replicate this behavior? I understand there are other, better defrag options out there but this problem has me perplexed.

share|improve this question
Have you deleted and recreated the task? – user3463 Jun 9 '12 at 21:08
I have, but doing so just brings me back to the beginning. The following reboot corrupts the task again. – Brian Jun 9 '12 at 23:19
That's useful to know. What happens when you add another scheduled task, but manually? – user3463 Jun 9 '12 at 23:32
Creating it manually seemed to do the trick, although now trying to open defrag gives me another message: Disk Defragmenter was scheduled using another program I can only remove the settings, which overwrites my manually-created task, or cancel. – Brian Jun 10 '12 at 1:07
I would like you to try Defraggler. Set it to replace the default, schedule a task, and see if it does the same thing. – user3463 Jun 10 '12 at 2:16
up vote 1 down vote accepted

Thanks for the recommendation! It looks like the issue only occurs when scheduling a monthly defrag ... a weekly task's integrity is still in tact after a reboot. I think I'm going to chalk this up as a bug. I've installed Defraggler though and will try it out as my system defrag.

share|improve this answer
I tried to set a Monthly defrag in Windows 8 and recieved an bona fide error message to the effect that the combination (monthly) is not compatible with the engine. – Guy Thomas Nov 25 '12 at 21:30
Thanks for the info! – Brian Jun 14 '13 at 20:53

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