Problem setting Mailspring as default mail client on KDE/Ubuntu 20.10

Bug Reports
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#1

I’ve installed Mailspring on my Kubuntu 20.10 system and finding it a really nice client. However, I’ve encountered one problem.

  • If I set Mailspring as the default mail client on the system (via KDE System Settings), I get an error when clicking links in my browser (Brave): Unable to create io-slave. klauncher said: Unknown protocol 'mailto'.and Mailspring doesn’t pick up the click to compose an email.
  • If I revert the default mail client to KMail (make change in System Settings and hit Apply) then I can use mailto links as expected.
  • If I reset to Mailspring (again, in System Settings and hit Apply), I get the same error.
  • If I use xdg-open 'mailto:foo@example.com' at the terminal then I get the same error (but not in a popup dialog, obviously).

Does anyone know what’s wrong here?

When I have KMail set as the default client, I have the following lines in my ~/.config/mimeapps.list:

[Added Associations]...
x-scheme-handler/mailto=org.kde.kmail2.desktop;mailspring.desktop;thunderbird.desktop;
...
[Default Applications]...
x-scheme-handler/mailto=org.kde.kmail2.desktop;

When I have Mailspring set, I have the following lines in the same file:

x-scheme-handler/mailto=mailspring.desktop;org.kde.kmail2.desktop;thunderbird.desktop;
...
x-scheme-handler/mailto=mailspring.desktop;
#2

I want to add that I can’t reproduce this issue on Ubuntu 20.04. It might be something with 20.10 only, or KDE.

#3

Yes, it’s different between KDE Plasma and Gnome Shell (which Ubuntu uses). Not least, Gnome doesn’t use klauncher. :confused:

#4

I can’t reproduce it with KDE under Ubuntu 21.04 either.

#5

Odd. I usually use the Brave browser, and get the reported error above (after it asks permission to use xdg-open). I just tried with Firefox and it just fails silently: Mailspring becomes the focused application, but no email is created.

Could you share what you’re using in KDE Settings > Default applications to launch mailspring?

Thanks!

#6

I’ve managed to fix this after much reading and various fiddlings about. I’m not sure what the problem was but I think what fixed it was to edit the file ~/.local/share/applications/mailspring.desktop so that the first two lines read:

Exec=mailspring %u
MimeType=application/x-xdg-protocol-mailto;x-scheme-handler/mailto;

The changes here are to add %u at the end of the first line, and to add application/x-xdg-protocol-mailto; to the MimeType declaration.

#7

I’m running KDE plasma on Arch (currently Plasma 5.24.5/Frameworks 5.94.0) and those edits don’t seem to be needed now. The x-scheme-handler/mailto seems to be enough for plasma to recognize it now, and the desktop file in the .deb has the %U already.