Is Ark the same thing as Software Center?
You can try Synaptic
I had to download a dot deb file from a website because it was not listed on synaptic, how to I tell synaptic to install the dot deb file from this other website? Or does synpatic only install programs from it own list?
You could easily double-click on the .deb file (or use apt) and install it.
Double clicking brings up Ark.
You can right click and then there will be an option called “Gdebi installer”, or if not, go to “open with”, and then go to “open with other application”, and find Gdebi. If not installed go to the terminal and type sudo apt install gdebi and enter in your password.
If there are any errors, or gdebi simply crash. You can install the .deb package via dpkg as the last fail-safe option by doing dpkg -i package.deb, and if there are any dependency error, type sudo apt install -f, and then re-type the first command (or press the up button twice to look into the history). And you’re done!