Defender Antivirus "turned off"

Hi kirbster 1

Since you're on a Windows 11 Release Preview build (25H2 26200.8968) and Defender is clearly updating, scanning, and all protection toggles are enabled, this may be a Windows Security reporting bug rather than Defender actually being disabled.

A few things to check:

1. Open PowerShell (Admin) and run:

      Get-MpComputerStatus | Select AntivirusEnabled, RealTimeProtectionEnabled, AMServiceEnabled
   

   If these return True, Defender is running despite the warning. Open services.msc and confirm Microsoft Defender Antivirus Service (WinDefend) is running. Reset the Windows Security app: Settings > Apps > Installed apps > Windows Security > Advanced options > Reset.
2. Run:

      sfc /scannow
      DISM /Online /Cleanup-Image /RestoreHealth
   

   Check if any third-party security software (including remnants from a previous install) is registered with Windows Security Center.

Because this is occurring on a Release Preview Insider build, if Get-MpComputerStatus shows Defender is enabled, I'd lean toward a false notification/reporting issue rather than a protection issue.

As this is a public forum, no one here can access internal builds to investigate this for you. You can submit feedback through Feedback Hub (Win + F) and include a screenshot plus a copy of the PowerShell output above.

Hope this will get sorted out soon!

Can confirm here as well, been like this for the past few insider builds, not entirely sure if it's Insiders related.. but i'm guessing it is.

Just wondering if either of the posters have a second AV

that could be turning it Off.

I'm seeing this on a normal build.

Apart from that warning it all looks fine, PS reports it's all enabled.

Seeing exact same symptoms for Defender Antivirus showing as off, but all the toggles showing as running (and I can use the right click context menu in Explorer to initiate an on-demand scan, so I know it's not all broken). I have no other antivirus installed, and I am not enrolled in insider; currently running the August 2026 normal update (build 26200.9168). Microsoft Defender Antivirus service was not showing up in Services.msc, either.

I ran Get-MpComputerStatus as suggested above and all three responded as if they were running. After running Get-MpComputer Status for the AV services, sfc /scannow, and the DISM check (no issues identified for either of the latter), the Defender AV Network service, Defender AV service, and Defender Core service all show up in Services.msc. I still have "Microsoft Defender Antivirus is turned off", but at least the services show up as running.

Whatever is causing this issue is not just for release preview builds, but I appreciate the alternative method to confirm that things are running via PowerShell.