Windows 8 and 8.1 Forums

Windows defender vanishes immediately after it starts

  1. #1

    Windows defender vanishes immediately after it starts

    Hello Guys, I am using a windows 8 pre-loaded laptop. My McAfee one-year-subscription will end this week, so I decided to uninstall it altogether and turn on Windows Defender. I tried to startup Defender from search in the charms bar, but on clicking on Windows Defender in the results, nothing happened. Moreover I got a error message saying that the file was not found.

    So, I went to the official windows 8 page and checked out what they had to offer, and I did all of those.

    1. I restarted my PC several times.
    2. I downloaded the McAfee Product Removal Tool, and used it.
    3. I did a malware scan using Microsoft Safety Scanner, it ran for about an hour and then finishes successfully after uninstalling 2 more of my programs.
    4. I did a SFC scan. It ended saying "Windows Resource Protection found corrupt files but was unable to fix some of them. Details are included in the CBS.Log %WinDir%\Logs\CBS\CBS.log."
    5. I restarted Windows Security Center Service.
    Upto this point, there was no effect. Defender wouldn't even startup.
    6. I deleted "conflicting Registry Entries". Specifically, I deleted these keys: MSASCui.exe, MpCmdRun.exe or MsMpEng.exe under HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Image File Execution Options.

    Now, when I start Defender, it starts up with the front screen showing "At risk".
    Click image for larger version
    As soon as I click "Start now" defender simply closes. And that's it. I did this many times but without any result, all it does is vanish as soon as I click "Start now".
    I'm in a real fix, because now my laptop has practically NO security or antivirus, please Help. Thanks.

      My System SpecsSystem Spec

  2. #2

    Posts : 2,067
    Windows 10 Home/ Windows 10 TP/ Windows 8.1 Pro/ Windows 7 Pro

    Try to start windows defender in safe mode.
      My System SpecsSystem Spec

  3. #3

    Okay, I tried to start it in Safe mode. This time, a different thing happened. As I clicked "Start now", the Defender actually started but only for 2 or 3 seconds, after which it automatically stopped. I retried but the same thing happenned. On starting it through Local Services, the same thing happenned. It started, but after a second or two, it stopped. What do I do now?
      My System SpecsSystem Spec

  4. #4

    Posts : 2,067
    Windows 10 Home/ Windows 10 TP/ Windows 8.1 Pro/ Windows 7 Pro

    Try sfc/scannow a couple of times in safe mode and reboot after each sfc/scannow in order to repair corrupt files.
      My System SpecsSystem Spec

  5. #5

    Posts : 374
    Win 8.1 64bit

    The first thing I would do is run Sfc /scannow at Cmd. Prompt with Adm. Privileges to check for file corruption.
    If any found run Dism /Online /Cleanup-Image /RestoreHealth same way then run Sfc /scannow again gator2013
    SFC /SCANNOW Command - Run in Windows 8

    Check the above tutorials.
      My System SpecsSystem Spec

  6. #6

    @AritraDas Dd you already solved your problem? Can you tell me how you solved it? I have also that problem. Thanks in advance.
      My System SpecsSystem Spec

Windows defender vanishes immediately after it starts

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