gdebi installer exits without installing the .deb file in 17.10

I have gdebi set as the default application to install .deb files. This way, I can just double-click on a .deb file and the gdebi installer will do the rest.

It seems that since 17.10, or one of its updates, this no longer works. I double-click on a .deb file, gdebi launches, showing the appropriate .deb file information, I click INSTALL, and gdebi just exits.

I have reinstalled all of the gdebi software components. No change.

However, in terminal, I type sudo gdebi some_filename.deb, it all works fine.

Any idea why the GUI doesn't work any more? I'm using xorg, not wayland.

Update #1: I have two machines with this problem. Both were upgrades to 17.10.

Update #2: If I manually open gdebi and manually select the .deb file to install, it all works fine.

Update #3: If I show properties of any .deb file, and try to change the "Open With" application, GDebi doesn't show up in the list of available applications.

Final Update: Late postnote... gdebi has problems in 18.xx too. It won't install .deb files when you double-click them... if they're on the desktop... it never asks for admin password. Anywhere else, it works as it should.

gdebi works in a fresh install of Ubuntu 17.10

gdebi (installed from the Ubuntu repo) works for me in a fresh install of Ubuntu 17.10 in text mode when started from a terminal window (like it works for you), but it works also in graphics mode even with Wayland after

xhost +si:localuser:root

as illustrated with the following screenshot

I think your problem is caused by something left from the previous version after the do-release-upgrade.

From what you wrote, it seems that gdebi cannot change to root mode after you press Install. In the terminal you are using sudo and it starts in root mode from the beginning. I'm pretty sure that if you start gdebi or modify its launcher to use gksu gdebi it will work fine.