Issue: Unable to Open Mailto Links in Firefox with Thunderbird Installed via Flatpak
When clicking on mailto links in Firefox, Thunderbird (installed via Flatpak) does not appear in the list of applications to handle these links. Even when manually locating and setting the Thunderbird binary (/var/lib/flatpak/app/org.mozilla.Thunderbird/x86_64/stable/active/files/bin/thunderbird), the application fails to open. However, running Thunderbird via the Flatpak command (flatpak run org.mozilla.Thunderbird) works as expected.
Solution: Register Thunderbird for the Mailto Protocol
To resolve this issue, I manually registered Thunderbird as the default handler for the mailto protocol in your system's MIME configuration.
Steps:
-
Edit the MIME Configuration File:
Open the
mimeapps.listfile in your preferred text editor:nano ~/.config/mimeapps.list -
Add or Modify the Mailto Handler:
Add the following line under the
[Default Applications]section:[Default Applications] x-scheme-handler/mailto=org.mozilla.Thunderbird.desktopIf the
[Default Applications]section does not exist, create it at the beginning of the file. -
Reconfigure Firefox Settings:
- When a
mailtolink is opened in Firefox, Thunderbird is now offered as an option to open the link.
- When a
Probable Cause:
Flatpak applications are sandboxed and often do not automatically register themselves with the system as handlers for specific protocols (like mailto). This results in Firefox being unaware of Thunderbird's ability to handle mailto links.