I had recently disabled windows defender on windows 10 and when I did I know want to enable it again but when I open action center and press Turn On Now it does nothing. I have pressed it multiple times and with no result. Fix: press Windows Key + R type regedit locate the following path * HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\WINDOWS DEFENDER* Right Click this file and select permissions press Advanced where it says owner press change change the owner to your username Now press apply then ok select Full Control from the permissions menu (click the Widnows Defender folder ) Find the value DisableAntiSpyware and DisableAntiVirus and set these values to 0 (explaination: double click each and where the 1 is put 0 and press ok) Open services.msc find Windows Defender there should be 2 services: Windows Defender Service and Windows Defnder Netwrok right click each and press start after you have started both restart your computer Run Windows Defend er I Hope this Helps! Feel Free to Reply

Fix: press Windows Key + R type regedit locate the following path * HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\WINDOWS DEFENDER* Right Click this file and select permissions press Advanced where it says owner press change change the owner to your username Now press apply then ok select Full Control from the permissions menu (click the Widnows Defender folder ) Find the value DisableAntiSpyware and DisableAntiVirus and set these values to 0 (explaination: double click each and where the 1 is put 0 and press ok) Open services.msc find Windows Defender there should be 2 services: Windows Defender Service and Windows Defnder Netwrok right click each and press start after you have started both restart your computer Run Windows Defend er I Hope this Helps! Feel Free to Reply

If none of the advice from this thread helps, please create your own new thread to get personal assistance. Ask a Question Thanks, David

This worked great, but only if Security center is turned off. As soon as security center turns on, it shuts off Defender and I can't start it until I disable the security center service, go back into the registry and change the values again. Once I do that, Defender will start up and run all day long. AS SOON as Security center is turned on, it kills Windows defender and I have to do the whole thing over again. Was working great up until yesterday when the latest Cumulative update was installed, then after the install I have been having these issues with Defender. Currently no other Antivirus installed, and Windows defender running fine with security center disabled

Not helpful, marcusransom :-( People are "putting all this up" because they're having problems ... duh??? Your reply sounds more like venting than helping. I only had MSE (Microsoft Security Essential) installed and running as the antivirus before upgrading from to Windows10 on my ThinkPad E545. Problems had been noted with MSE installed prior to upgrading and some solutions including backing out of Windows10 to what was previously installed, removing MSE and all of its components, and reinstalling Windows10. Fortunately, I didn't have to do that. I, too, reviewed all possible causes noted on this community forum before attempting to make any fixes and before making my post.

Windows 10: Windows Defender will not turn on SOLVED

Anonymous

I had recently disabled windows defender on windows 10 and when I did I know want to enable it again but when I open action center and press Turn On Now it does nothing. I have pressed it multiple times and with no result.

Fix:

press Windows Key + R
type regedit
locate the following path *HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\WINDOWS DEFENDER*
Right Click this file and select permissions
press Advanced
where it says owner press change
change the owner to your username
Now press applythen ok
select Full Controlfrom the permissions menu

(click the Widnows Defender folder)

Find the value DisableAntiSpyware and DisableAntiVirus and set these values to 0

(explaination: double click each and where the 1 is put 0 and press ok)

Open services.msc
find Windows Defender
there should be 2 services: Windows Defender Serviceand Windows Defnder Netwrok
right click each and press start
after you have started both restart your computer
Run Windows Defend er

I Hope this Helps!

Feel Free to Reply

Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.

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Answer accepted by question author