Windows 11 Defender Firewall Will Not Load

[Sparky]

Windows Defender Firewall works fine in Windows 10. Immediately after an upgrade to Windows 11 Firewall loads and works. After a reboot the Firewall will not load. There is no other firewall installed. Any selection in Control Panel Windows Defender produces an error. Windows Defender Firewall Service is continually toggling between "Running" and "Starting". All network selections in Windows Security/Firewall Network and Protection are grayed our. Any attempt to poll Defender status in command prompt produces an error.

 

[OldTechy]

Guys, you all have an ASUS mobo, or?

Solution:
Full credit goes to the authors of:
1) https://www.techpowerup.com/248827/...-push-software-into-your-windows-installation
2) https://twitter.com/HpDream

Long story short:
The ASUS UEFI Bios installs an exe file AsusUpdateCheck.exe and configures it as a service on each boot UNLESS you disable this in the UEFI bios, see 1).
Under certain circumstances this services adds an entry to the DebugedLoopbackApps on each invocation.
The variable DebugedLoopbackApps is maintained by the standard windows utility CheckNetIsolation.exe see 2).

So, still on W10 I disabled the start of the ASUS utility in the Bios and then could see with

CheckNetIsolation.exe loopbackexempt -s

that I had more than 1000(!) identical entries of S-1-15-2-490905099-2794809881-2632752266-3514030558-4166392763-3416490339-321513134 in DebugedLoopbackApps.

These could easily be deleted with

CheckNetIsolation.exe loopbackexempt -d -p=S-1-15-2-490905099-2794809881-2632752266-3514030558-4166392763-3416490339-321513134

upgrade to W11, done.

hello, I have been studying your post with great earnest . I know 2 yrs old...
But I can find nothing else posted that has fixed these Windows 11 DEfender - Firewall failures afte update from Win 10 on ASUS Mobo..
the link shown in solution 2) redirects to a post in Asian language , I can;' read it..
Is there an UPdated link or can you suggest an Alternate link/location to read that posting?
thank yo for you assist...
REgards