“It’s not just you: Flatpak flat-out doesn’t work in the new Ubuntu 25.10 release,” writes the blog OMG Ubuntu:
While Flatpak itself can be installed using apt, trying to install Flatpaks with Flatpak from the command-line throws a “could not unmount revokefs-fuse filesystem” error, followed by “Child process exited with code 1”. For those who’ve installed the Ubuntu ‘Questing Quokka’ and wanted to kit it out with their favourite software from Flathub, it’s a frustrating…








