Windows 10: Can't run Windows Defender

Win Defender Security Centre lists my Virus and Threat Protection as disabled. The message reads "Your Virus & threat Protection is managed by your organization."

This happened a month ago and was resolved when I thoroughly removed Malwarebytes, though it and Win Defender had co-existed without trouble for some years. Now Malwarebytes is gone, no other antimalware software in place. Anyone suggest what could be disabling Win Defender?

:)

 

Windows Defender problem

Hi Ernst,

To troubleshoot this issue, we suggest that you check the Windows Defender service if it's running. If you are using a third party spyware/malware program, it may disable the Windows Defender service. To do this, please follow the steps below:

• Press Windows + R key.
• Type services.msc.
• Right-click Windows Defender service and click
  Start.

Let us know the result.

 

Windows Defender Not On

Hi,



Welcome to Microsoft Community. Your interest in Windows 10 is much appreciated.



I would suggest you to try the below methods and check:

Method 1:

I would suggest you to run virus scan to make sure the computer is free from virus.

The Microsoft Safety Scanner is a free downloadable security tool that provides on-demand scanning and helps remove virus, spyware, and other malicious software. It works with your existing antivirus software.

http://www.microsoft.com/security/scanner/en-us/default.aspx



Method 2:

Turn the Defender on. Follow the below steps:

• In search, type Defender.
• Now make the option ON by moving the slider accordingly.

Method 3: Run the SFC.

Follow the below steps:

• Open Command Prompt.

• Select “Run as Administrator”.
• Type “sfc /scannow” without quotes and hit
  Enter.

Now check for the issue.



Keep us posted if you face any issues on windows in future. We will be glad to help you.

 

Windows defender's process running despite it being disabled.

Windows Defender is integrated within Windows 10. So you have it and it is running (as it should be) unless you installed a 3rd party "real-time" anti-malware solution. If you are using an alternative security solution, it should have registered itself with Windows Action Center which would then disable the real-time component of Windows Defender - unless you specifically told the 3rd party solution not to register itself.

For example, if you purchased Malwarebytes "Premium", it has a real-time scanner (the free version does not). When you install Malwarebytes Premium, it registers itself in Windows Action Center. But because Malwarebytes and Windows Defender play very well together without hogging resources or causing conflicts, it is often recommended to allow each to run at the same time. So to allow that, the user has to manually go into the Malwarebytes control panel Settings menu and select the option to "Never register Malwarebytes in the Windows Action Center".

I suspect other 3rd party solutions provide similar options so you might check that out if you did indeed, install a 3rd party security solution.

Both Windows Update and Windows Defender are supposed to step way back in to the background so they do not interfere with system performance when you are actively using your computer. But this is not always possible, especially if you regularly shut down your computer when you step away from it (instead of just letting it go to sleep), as too much time may have passed and your system is too far behind in Windows and security updates.

Without you noting which program was actually consuming the lion's share of that 80%, there's no way to tell what, at this point, was causing the problem. However, I would not put it past a browser. Chrome, for example, is very good (or bad, I should say) at eating up a lot of RAM and failing to let it go when exited.