# Windows Defender Won't Start



## stevemackenzie (Jun 27, 2013)

Hi, looking for some help with Windows Defender on Windows 10.

Last night, it looks like there was a malware detected.

Today, I can't get Defender to start. When I click on Defender through Start, I get a message stating "The app has been turned off and isn't monitoring your computer".

I tried to turn on Defender thru services.msc but get an error stating "Error 577: Windows cannot verify the digital signature..."

I have scanned using Malwarebytes and Superantispyware but neither found anything.

I'm worried I have something nasty on my PC.


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## flavallee (May 12, 2002)

Windows Defender is the default antivirus program for Windows 10.
Have you installed another antivirus program?


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## stevemackenzie (Jun 27, 2013)

flavallee said:


> Windows Defender is the default antivirus program for Windows 10.
> Have you installed another antivirus program?
> 
> View attachment 243808


Hi, I have bit defender installed.


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## CoolBurn (Dec 5, 2013)

stevemackenzie said:


> Hi, I have bit defender installed.


That would be the reason.


> You should never *run* more than one *antivirus* program at the *same time*. The *two* programs could slow down your computer, and they might even identify each other as a virus, which could lead to file corruption or other conflicts and errors that make your *antivirus*protection less effective-or not effective at all.


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## flavallee (May 12, 2002)

A computer shouldn't have 2 antivirus programs installed and running at the same time.
When you installed *BitDefender*, it should've disabled *Windows Defender*.
That's why you're seeing the message you mentioned in post #1.

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## stevemackenzie (Jun 27, 2013)

flavallee said:


> A computer shouldn't have 2 antivirus programs installed and running at the same time.
> When you installed *BitDefender*, it should've disabled *Windows Defender*.
> That's why you're seeing the message you mentioned in post #1.
> 
> -----------------------------------------------------------------


Thanks. Does this apply to even though both apps have been running on the pc together for the past couple of times?


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