Windows 10: Unable to open Windows Defender


  1. Posts : 7
    Windows 10 - 64bit
       20 Nov 2016 #1

    Unable to open Windows Defender


    While I was away someone tried to make changes to my system. I am trying to enable Defender, but I receive the attached message;Click image for larger version. 

Name:	Defender.PNG 
Views:	26 
Size:	9.9 KB 
ID:	110858
    I am the administrator.
      My ComputerSystem Spec


  2. Posts : 824
    Win10/64 Pro 1511 (and 2 Win 7/64 Ult & Pro systems)
       20 Nov 2016 #2

    Hi:

    See here:
    Windows Defender - Turn On or Off in Windows 10 - Windows 10 Forums

    But the more fundamental (and worrisome) question: who accessed your system while you were away?
    The reason I ask is that it's possible that this person may have made other changes that compromised your security, personal information, etc.
    I'm not trying to create fear or paranoia, just mentioning it, in case you want help checking the system...

    MM
      My ComputerSystem Spec


  3. Posts : 7
    Windows 10 - 64bit
    Thread Starter
       20 Nov 2016 #3

    Hi MM; I'll let you know how I made out tomorrow, after making a printout and reading all instructions. I'm not too worried about someone accessing my system - I've made an image just in case, but I will put in a password to my account. Thanks again.
      My ComputerSystem Spec


  4. Posts : 3,503
    Win10 Home and Pro, Win10 Insider Preview, Win7 Home, Linux Mint
       20 Nov 2016 #4

    Also, if another AntiVirus program was installed, or attempted to be installed, it could have turned off Windows Defender. I've found it usually gets restored when Uninstalling any other AV program. Sometimes have to go to Control Panel, Windows Defender to turn it on.
      My ComputerSystem Spec


  5. Posts : 824
    Win10/64 Pro 1511 (and 2 Win 7/64 Ult & Pro systems)
       20 Nov 2016 #5

    Berton said: View Post
    Also, if another AntiVirus program was installed, or attempted to be installed, it could have turned off Windows Defender. I've found it usually gets restored when Uninstalling any other AV program. Sometimes have to go to Control Panel, Windows Defender to turn it on.
    Excellent ideas.
    If someone else accessed the computer, who knows what they might have installed.

    If WD is disabled by Group Policy, however, would one be able to enable it merely via the Windows CP, or would one not have to reverse the GP edit or registry change?
    <just asking, trying to learn>
    FWIW, on my Win10 box running KIS, the WD settings are grayed out. I do not even get a way to try to enable it.
    And I do not see the GP message, either, even though I am on Win10 Pro and have other GP edits in place.

    So I guess my question is: when one installs a 3rd-party AV that disables WD, does it generate that GP edit message or does it just disable WD and make its settings inaccessible?

    Ennywho, @benton, please let us know how it goes.

    Cheers,
    MM
      My ComputerSystem Spec


  6. Posts : 3,503
    Win10 Home and Pro, Win10 Insider Preview, Win7 Home, Linux Mint
       21 Nov 2016 #6

    MoxieMomma said: View Post
    If WD is disabled by Group Policy, however, would one be able to enable it merely via the Windows CP, or would one not have to reverse the GP edit or registry change?
    <just asking, trying to learn>
    I believe the installation routines make the change, mainly based on the fact the Home version of Windows don't have the Group Policy Editor [not usually needed] and in turn should change things back when uninstalled. As has been noted in many posts the uninstall routines can go awry, necessitate other procedures to clean them up.
      My ComputerSystem Spec


 

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