I have recently set up a new development machine (Lenovo T440p laptop with Windows 8.1 Pro), and this event keeps getting logged to the Event Log (about once every 2.5 minutes):

The Windows Security Center Service could not stop Windows Defender.

I have Windows Defender turned off and have Trend Micro Security Agent installed and running. The Action Center shows both "Virus protection" and "Spyware and unwanted software protection" as On, with Trend Micro listed below them. In the Services console, the Windows Defender service is set to Manual start up and is not running. I tried setting the start up type to Disabled (through the registry, since the option is grayed out in the services console), but the event keeps coming up every 2.5 minutes.

If Windows Defender is not running, and the service is in fact disabled, why am I getting a message that it could not be stopped? It's not running to begin with. It doesn't throw any errors, cause any popups or notifications on my machine, or in any way prevent my computer from functioning properly. However, I use this machine for software development, and all of my software writes to the event log. I almost always have it open and monitor it for errors, information, and general output from my software. The occasional system event or event from another application mixed in is fine (and expected), but this message popping up every two minutes is cluttering the event log unnecessarily, and as far as I can tell, shouldn't be happening.


Try running:

DISM /Online /Cleanup-Image /RestoreHealth

In CMD with Admin privileges, then:

sfc /scannow

afterwards. Reboot (without fast restart enabled in Power Options). If the problem is related to corrupt files, this should fix it. Also, you could try different AV software (I use Avast free) to make certain that the issue is not with your AV.

  • Thanks for the suggestions! I'll give the DISM command a try and see if it helps. I've already tried sfc /scannow (that's one of my go-to troubleshooting steps) without success. Also, since this is a work computer, I don't have a choice about what AV software to use. It has to be TrendMicro. Still, it was a good suggestion, so thanks again! – TheRotag Jan 8 '16 at 15:40

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