Windows 10: Windows Defender updates failed, service won't start

The last few days, Defender has been trying and failing to update its definitions. A manual update from Defender fails. Now Defender isn't working. Pressing Defender's Start button gives the message that the underlying service isn't running. The service is set to automatic, it can be started but immediately stops.

Is there any known way to repair this short of a Windows refresh?

:)

 

After Update "Windows Creator Update" version 1703 i can't update

After that update i try to update, i try to update such window defender but failed it appear like this it won't move at all. I already make the service stop and restart but won't do anything .

 

Windows Defender Won't turn on

I too am having a problem with Windows Defender after updating to version 1511.

When trying to start the Windows Defender Service I receive a message 'Error: 0x80070005 Access is denied'

I tried starting the Windows Defender Network Inspection Service first and then the Windows Defender Service but I still get the same error message. The Windows Defender Network Inspection Service appears to start correctly and continues to run, but the
Windows Defender Service begins to start and then I receive the above message.

When I run C:\Program Files\Windows Defender\MSASCui.exe and then click on 'start' it appears to try and start but all I see is the spinning circle cursor. It eventually fails and gives an error: 0x800705b4

I have followed the trouble shooting guide without success and running sfc /scannow tells me that 'Windows Resource Protection found corrupt files but was unable to fix some of them. Details are included in the CBS.log ....'

Any suggestions on how to resolve this issue would be greatly appreciated.

 

Hello markweatherill:

Some security products of other companies may intentionally disable Windows Defender to prevent mutual interference.

Besides Windows Defender, has any other security product been installed on the system with Windows 10?

Thank you.

 

go to the tutorial for problem getting up dates

it worked for me, but i still need to that every other day but it works
i'll look for it and try to send the link

 

I made a Windows 10 ISO, updated Windows 10 and it 'fixed' the problem.