You're right that I didn't have that plugin package installed. I installed it and double clicking the package still presents the same error. Apologies I omitted the screenshot in my initial report.
** Attachment added: "Screenshot from 2017-09-11 16-58-06.png" https://bugs.launchpad.net/ubuntu/+source/gnome-software/+bug/1716409/+attachment/4948014/+files/Screenshot%20from%202017-09-11%2016-58-06.png -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1716409 Title: Unable to install flatpak on Ubuntu artful To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-software/+bug/1716409/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs