Current default browser isn't compatibile - Firefox MSIX

[hwfanatic]

Malwarebytes doesn't seem to recognize that Browser Guard is installed in Firefox. It claims that my "current default browser isn't compatible". I use Windows 64-bit MSIX package (downloaded and installed from Microsoft Store).

If I change my default browser to Microsoft Edge, I don't have this issue and everything is in the green.

At first I thought this was caused by having previously used the regular desktop version of Firefox. This condition will leave your profiles in
%APPDATA%\Mozilla\Firefox
and
%LOCALAPPDATA%\Mozilla\Firefox
respectively and use them from there. After extensive testing I can only conclude this is irrelevant.

My test was as follows.

I have renamed these two folders to Mozilla-backup. I have reset the Firefox app through Settings->Apps->Installed apps->Firefox. Running the app after that cause it to create default profiles in
%LOCALAPPDATA%\Packages\Mozilla.Firefox_n80bbvh6b1yt2\LocalCache\Roaming\Mozilla\Firefox
and
%LOCALAPPDATA%\Packages\Mozilla.Firefox_n80bbvh6b1yt2\LocalCache\Local\Mozilla\Firefox
respectively. I've installed Browser Guard in the default profile. Malwarebytes is still showing my browser as not compatible.

Surely this is some sort of problem on your end. It seems that the MSIX package is not supported for whatever reason.