As others have suggested this is a snap app issue with /tmp dirs and can be verified with:
gnome-software --local-filename '/tmp/mozilla_user0/app_amd64.deb' snap-store --local-filename '/tmp/mozilla_user0/app_amd64.deb' I have added workaround to AU to use 'gnome-software' for opening debs: https://askubuntu.com/a/1330582/8570 I did also find an alterntive workaround so that all snap apps have access to /tmp: https://askubuntu.com/a/1264341/8570 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1908469 Title: Cannot install .deb packages opened from Firefox To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1908469/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
