Windows 10 - Microsoft Security Client Error Code 0x80070426

Windows 8.1

Asked by: KevinOhYes

After the Windows 10 update that I installed on Tuesday, 1/10/17, my computer has been a wreck.

1. My computer is extremely sluggish, gaming is impossible and even opening up the Task Manager takes 10 seconds. I fear my computer has a virus.

2. I wanted to scan my computer using Windows Defender, but I noticed Windows Defender does not appear in the icon box that's in the lower right side of the desktop. However, Task Manager says it is running (I found WinDefend under the services tab). HOWEVER, I cannot open up Windows Defender through the Update & Security page. That is when I get the error code above, Microsoft Security Client Error Code 0x80070426.

3. I have tried Offline Windows Defender scan - Didn't work.

I looked online, only to see that the solution is to uninstall Microsoft Security Essentials, which I don't have installed according to the List of Programs on the Control Panel. 

I tried contacting Microsoft support, in which they told me to restore my computer to a previous state - Didn't work and got an error message, telling me it failed to restore due to no access to some sort of Cortana file. 

I can't seem to run as an administrator and my computer fails to see that I am the owner and only user of the computer.

Here's some basic information about my computer, please let me know if you need more info.

Dell XPS 8100

Windows 10 - Upgraded from Windows 7 Home. Both were geniune since I bought the desktop straight from Dell, then upgraded to 10 once I got the option to.

Do not have multiple OS or users

Started to happen after the update released on 1/10/17. 

I used Avast for the longest time until Windows Defender became mandatory for Windows 10 systems, so I uninstalled and started using Windows Defender solely. 

None of this EVER happened until Wednesday, the day after.

Basically, I have a feeling one of the problems is with these updates:

1. Cumulative Update for Windows 10 Version 1607 for x64-based Systems (KB3213986)
2. Windows Malicious Software Removal Tool for Windows 8, 8.1, 10 and Windows Server 2012, 2012 R2, 2016 x64 Edition - January 2017 (KB890830)
3. Security Update for Adobe Flash Player for Windows 10 Version 1607 (for x64-based Systems) (KB3214628)

Or it's a virus that somehow disabled Windows Defender and blocks my access to administrator priveleges. 

Anyone got a clue?

Files, folders & storage 12/01/2017 0 Comment 49 views

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