Mainloop.source_remove, not Mainloop.remove_source. Also, GConf key /desktop/gnome/url-handlers/mailto/command is deprecated and likely to be invalid. You should retrieve and launch the GAppInfo for x-scheme-handler/mailto. Finally, spawning two python helpers (one of which using python3) is by far an overkill. Try using camel instead of imaplib, and libedataserver instead of manually parsing GConf blobs.

Fixed remove_source -> source_remove Now using GAppInfo for x-scheme-handler/mailto to launch MUA. The last issue is problematic. First, there are no GIR bindings for Camel as far as I can see. Second, the libedataserver GIR bindings are incomplete. I have left some commented-in code in the version 2 upload: EDataServer.Account.new_from_xml(xml) works fine, but the only method that can be called on it successfully is to_xml(). Basic methods like get_string and get_bool result in an error (no such function) despite those methods being documented in the GIR interface /usr/share/gir-1.0/EDataServer-1.2.gir. It would have been nice to use only one python script to achieve this. However, the GConf and gnome-keyring bindings only exist for python 2 and not python 3, yet python 2 imaplib does not support STARTTLS which is vital in order not to have people's email passwords going out in plain text. If you have any further suggestions I would love to hear them.