Windows 10: Can't turn on,scan or any other thing through Windows Defender

I can't scan through my windows defender even I can't see the scan dialogue windows.When I tried to turn it on then the following windows have shown...

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defender scans

Hi Ian,

Thanks for posting your query on Microsoft Community.

This issue might occur if you have set any task scheduler for Windows Defender.

I suggest you to delete the task for Windows defender and check if it helps.

Follow the below steps:

• 
  Search and open Schedule tasks.
  
• 
  In the left-hand menu, open the Task Scheduler Library, then select
  Microsoft >Windows >Windows Defender.
  
• 
  Double-click Windows Defender Scheduled Scan.
  
• 
  Select the Triggers panel, then select Delete.
  

Hope it helps, reply to us with the status of your issue. We will be happy to assist you.

 

WINDOWS DEFENDER is turned off

Hi Ahmed,

Since you're not able to turn on Windows Defender as well, we'd like to know if you have made any changes recently prior to this issue. In the meantime, you may follow the steps below on how to turn on Windows Defender manually:

• Type Windows Defender in the Search bar and press
  Enter.
  
• Go to Settings and make sure that the Turn on real-time protection recommended option is turned on.
  

Same thing with the other members who are having the same issue, we suggest that you check if the service was setup to
Automatic in the Services option. Please follow the steps that we've provided last
September 3, 2017.

Let us know how if you were able to turn it on properly by changing the Startup type to Automatic.

 

Windows Defender for Windows 10 will not turn on for Occasional Scanning

Windows Defender for Windows 10 will not turn on for Occasional Scanning on my PC. I have WebRoot SecureAnywhere for as my main antivirus software. If I change the settings in Windows Defender Security Center to turn to Occasional Scanning to ON, and Click
OK in UAC, as soon as I do that, Windows Defender Security Center Occasional Scanning turns OFF.

Does anyone have any suggestions on how to fix?

Thanks.