How to Remove Unused Flatpak Runtimes on Linux

What Causes This?

Flatpak apps rely on shared runtimes to work, and Linux often keeps older or no-longer-needed runtimes after apps are updated or removed. Over time, these leftover packages build up and take unnecessary disk space. This usually happens after uninstalling Flatpak apps, switching app versions, or updating runtimes without cleaning up unused dependencies.

Common Symptoms

• Your Linux system is low on disk space for no obvious reason
• The ~/.local/share/flatpak or system Flatpak folders are using a lot of storage
• You see old Flatpak runtimes listed even though the related apps are gone
• Flatpak updates seem to download or manage more data than expected
• Storage cleanup tools show large amounts of app-related data

How to Fix It Manually

1. Open a terminal

   • On most Linux systems, press Ctrl+Alt+T.
   • If that does not work, open your app menu and search for Terminal.

2. Check which Flatpak apps and runtimes are installed

   • Run:

     flatpak list

   • This shows installed apps and runtimes. Runtimes are shared components used by multiple Flatpak apps.

3. Remove unused Flatpak runtimes automatically

   • Run:

     flatpak uninstall --unused

   • Flatpak will scan for runtimes and extensions that are no longer required by any installed app.
   • Review the list carefully, then confirm the removal when prompted.

4. Remove unused items for system-wide Flatpak installs if needed

   • If you installed Flatpak apps for all users, run:

     sudo flatpak uninstall --unused

   • Enter your password when prompted.
   • This cleans up unused system-wide runtimes stored outside your home folder.

5. Check for orphaned app data

   • Some removed apps may leave cached or user data behind.
   • You can inspect the user Flatpak folder with:

     du -sh ~/.local/share/flatpak

   • For system-wide installs, you can also check:

     du -sh /var/lib/flatpak

6. Update Flatpak packages after cleanup

   • Run:

     flatpak update

   • This makes sure your remaining apps and runtimes are current and not depending on outdated components.

7. Restart apps or reboot if storage still looks incorrect

   • Close any running Flatpak apps and reopen them.
   • If your file manager or storage tool still shows old usage numbers, restart your PC and check again.

8. Verify the cleanup worked

   • Run:

     flatpak list

   • Compare the results to what was installed before.
   • You can also recheck folder size with:

     du -sh ~/.local/share/flatpak

Fix It Automatically with Kudu

Kudu can scan your system for leftover app components, unused package data, and other storage-wasting files without making you dig through terminal output. It gives you a simpler way to spot cleanup opportunities and remove unnecessary data safely, including space used by old app runtimes and related leftovers.

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