Windows 10: I cannot turn on Windows Defender Antivirus.

I cannot turn on Windows Defender Antivirus. I entered the "Windows Key + R" (run program) keyboard shortcut. I entered "control" and pressed "Enter". I clicked on "System and Security". Then I clicked on "Security and maintenance". In the "Security and Maintenance" window, in the "Security" drop down list, "Virus Protection" is "Off" and I read that "Windows Defender Antivirus is turned off and is currently being managed by your system administrator." How to turn on Windows Defender Antivirus?

:)

 

Defender AntiVirus

There are 4 options under Defender. Two refer to AntiVirus; AntiVirus Network Inspection Service & AntiVirus Services. Under Startup Type these two are listed as manual and the Status column said Inspection Service is running. When I clicked on the Start
button in Properties, I got an immediate message: "Win.. Def.. Anti.. Serv.. on local comp.. started and then stopped. Some services stop automatically if they are not in use by other services or programs."

 

Can't turn on Windows Defender Antivirus

After freshly installing Windows 10 N and doing a few initial restarts to finish all updates, I cannot turn Windows Defender on anymore. After pressing "Turn on now" under Security and Maintenance at Virus protection, I get this message:

Security and Maintenance can't turn on Windows Defender Antivirus. Please try again later.

I tried disabling the "Turn off Windows Defender Antivirus" in policy editor, but that did not solve the problem. I also can't even open the Windows Defender Security Centre and I haven't installed any other antivirus.

 

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.