Why does Ubuntu 18.04 refuse to install .deb packages?

Question

Graphic shells

Basically, the question is in the title. It installs through the console, but by double-clicking on the package, a window pops up with the name of the program, description, screenshots, and the green “install” button on the left. When you click on it, nothing happens from the word at all =)). Where to dig? xfce working environment

Answer 1

1. Try to search xfce for "bindings" of file extensions to the corresponding programs. What is indicated there for deb-files?
2. If point 1 does not work, you can try to launch the file manager from xterm and then "run" the deb file by double clicking. The xterm should display progress or error messages.

Answer 2

I already answered you on the ubuntu forum how to try to fix this trouble.
Duplicate here as well
. click on the .deb package and in the drop-down context menu left on Properties , and in the drop-down properties window left on the tab at the top Open with .
In the window, look for GDebi Package Installer , select it with the mouse (click on the name) and click on the book. bottom right Set as default . Close the window...
Now, when you click on a .deb package, it will be installed in GDebi ...
In general, you have already been told that you can successfully do this in the Console (Terminal).

sudo dpkg -i /путь_к_папке_где_.deb-пакет/имя_пакета.deb