Canonical's Ubuntu 25.10, released with upgrades like GNOME 47 and Linux 6.11 kernel, has encountered problems with Flatpak applications shortly after launch. The glitch arises from changes in the AppArmor security module, causing installation and runtime errors. Canonical is working on a fix through upcoming updates.
Ubuntu 25.10's rollout, which began around early October 2025, has been marred by issues affecting Flatpak, a popular format for sandboxed applications across Linux distributions. Users reported installation failures and runtime errors, such as “revokefs-fuse unmount” failures, when trying to use Flatpak packages. This problem stems from modifications to AppArmor, Ubuntu's mandatory access control system, which was tightened in the new release to bolster security but inadvertently interfered with Flatpak's use of FUSE for virtual file systems.
This is not the first such conflict; similar AppArmor-related issues impacted Telegram's Flatpak apps in Ubuntu 24.04 LTS earlier in 2025. Canonical engineers have confirmed the bug as an oversight in testing, not intentional disruption of Flatpak, which competes with Ubuntu's favored Snap packaging. Patches are in development and expected via software updates soon, potentially avoiding the need for full reinstalls.
The incident underscores tensions in the Linux ecosystem between Flatpak—supported by Red Hat and the GNOME project—and Canonical's Snap, which prioritizes compatibility across Ubuntu variants. As far back as 2023, Ubuntu flavors were prohibited from including Flatpak by default to encourage Snap adoption. For enterprise users, the glitch may delay migrations, as Flatpak often hosts essential tools like development IDEs.
Sources such as ITSFOSS described Flatpak as “completely unusable” out of the box in Ubuntu 25.10, recommending users stick to DEB packages or Snaps as workarounds. Community forums, including Hacker News, show mixed reactions: some express frustration and speculate on biases against Flatpak, while others view it as a common non-LTS release hiccup. Canonical's response includes AppArmor profile adjustments, with guides from OSTechNix offering temporary fixes. This event highlights the challenges of integrating third-party formats while enhancing security, as Ubuntu prepares for its 2026 LTS release.