[Software] Firefox no longer works after 25.04 new installation

[phands]

Anyone else seeing firefox fail to launch with missing profile issues after installing the new release?

No matter what i do, I get a popup saying

Your Firefox profile cannot be loaded. It may be missing or inaccessible.

I also see lots of this on the shell..

firefox --first-startup --allow-downgrade
[54174] Wayland Proxy [0x76cb1d691250] Error: StartProxyServer(): bind() error : Permission denied
[54174, Main Thread] WARNING: Failed to parse /home/test/.config/gtk-3.0/settings.ini: Permission denied: 'glib warning', file /build/firefox-guXRMo/firefox-137.0.1+build1/toolkit/xre
/nsSigHandlers.cpp:201

(firefox:54174): Gtk-WARNING **: 11:40:49.164: Failed to parse /home/test/.config/gtk-3.0/settings.ini: Permission denied
[54174, Main Thread] WARNING: Theme parsing error: gtk.css:1:0: Failed to import: Error opening file /home/test/.config/gtk-3.0/gtk.css: Permission denied: 'glib warning', file /build
/firefox-guXRMo/firefox-137.0.1+build1/toolkit/xre/nsSigHandlers.cpp:201

(firefox:54174): Gtk-WARNING **: 11:40:49.164: Theme parsing error: gtk.css:1:0: Failed to import: Error opening file /home/test/.config/gtk-3.0/gtk.css: Permission denied
Fontconfig error: No writable cache directories
Failed to load cookie file from cookie: Permission denied

I'm using firefox as a .deb, as the snap stuff is unusable.

[phands]

Just because I had no other option, I also tried to install the snap version. It fails as well...with...

cannot perform the following tasks:
- Run install hook of "firefox" snap if present (run hook "install": cannot perform operation: mount --rbind /home /tmp/snap.rootfs_vFFtmy//home: Permission denied)

[kapustin]

I use Kubuntu 25.04 (installed from scratch) and “Firefox Snap” works well.

Regarding “Firefox deb”, did you follow the instructions here?

[phands]

Yes, I followed the instructions for using a deb file, thanks. I've done this a few times, as firefox using snap is an awful experience. This was a fresh install from the 25.04 iso, to a new disk partition. I also tried to as a brand new user from scratch...same issue.

[tenplus1]

I tend to do a minimal install for Kubuntu then install Firefox from the .deb file and skipping any snaps, makes for a more stable Os.

[kapustin]

If nothing works, you can circumvent the problem by downloading “firefox-137.0.2.tar.xz” from the Mozilla site; you have to extract it with Ark and place it in a folder of your choice. It is automatically updated each time you open it by double-clicking on “firefox”.