Windows 11 Security Dashboard no longer working.

So I upgraded from 10 to 11 but since then security dashboard has a yellow triangle over the icon and if I try and run it the border of the app appears only briefly...similarly when I try from settings the same thing happens? Not even sure how important it is because I do not seem to have any virus or malware. Carlos TJ gave me some advice and gave a link to do a 'Repair Install' but am not sure how to go about that? Any advice appreciated. Thank You. Ian Roe, Yorkshire, England, UK
NB: I have a formatted USB stick as drive E: with 32GB free if that helps.
Edition Windows 11 Home
Version 21H2
Installed on ‎28/‎08/‎2021
OS build 22000.466
Experience Windows Feature Experience Pack 1000.22000.466.0

Woe2022 said:

So I upgraded from 10 to 11 but since then security dashboard has a yellow triangle over the icon and if I try and run it the border of the app appears only briefly...similarly when I try from settings the same thing happens?

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Welcome to Eleven Forum

Did you have any 3rd-party AV installed when you upgraded from 10 to 11? If so it may be causing this problem, you want to try uninstalling it now.

I have a similar issue, my security won't even open. When attempting to start defender in services.msc I get this message: The Windows Defender Serviceservice on Local Computer started and then stopped. Some services stop automatically if they are not in use by services or programs. Any ideas are welcome and I've tried so many different things. I have Malwarebytes premium installed and even uninstalled that and still the same.

200motels said:

I have a similar issue, my security won't even open.

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Welcome to Eleven Forum

Woe2022 said:

....gave me some advice and gave a link to do a 'Repair Install' but am not sure how to go about that?

Click to expand...

An in-place repair upgrade can fix a lot of things, and keeps all your installed apps and files. This Eleven Forum tutorial shows you how.

With attached batch script, you can reset Windows Security app in Windows 11.

Bree said:

Welcome to Eleven Forum

Did you have any 3rd-party AV installed when you upgraded from 10 to 11? If so it may be causing this problem, you want to try uninstalling it now.

Click to expand...

Hello Bree, no I did not only the Windows security essentials that came with Windows 10...I am really not sure how big a problem this really is and am now thinking it could just be running in the background? Somebody else here is also suffering from this issue. The only AV software is what came with Windows 11 when it upgraded me. Thank you. Ian Roe

Woe2022 said:

..I am really not sure how big a problem this really is and am now thinking it could just be running in the background?

Click to expand...

There are two parts to Windows Security, the actual AV protection and the user interface (GUI) that allows you to control its settings. It's your GUI that isn't opening, but your AV protection is probably running. You can check for that by opening Task Manager (if it says 'More details' at the bottom, click on it). In the Details tab you should see MsMpEng.exe running, that's the AV protection engine.

I have seen a problem with the Windows Security GUI once before. An in-place repair upgrade fixed it.