16.04privacysnapsoftware installationsoftware-center
Today I wanted to install a Snap Package on Ubuntu Xenial, but it prompted me to register an account on Ubuntu Single Sign-On.
Why does Ubuntu ask us for such a thing?
Installing a Snap Package:
This is the reported bug on Launchpad, https://bugs.launchpad.net/ubuntu/+source/software-center/+bug/1581713
It is a known and reported bug https://bugs.launchpad.net/bugs/1616943
you can install it manually by typing
sudo snap install krita
in the terminal.
For some reason, both my Ubuntu Software Center (now simply called "Software") and the Snap Store weren't present on my Fresh Ubuntu 20.04 install. To install them, simply run the following two commands:
sudo apt install gnome-software # "Software"
snap install snap-store # Snap Store
Here's what their icons look like now when I press the Super key (Windows key on a PC keyboard, or Command key on a Mac running Linux), then search for them:
Ubuntu Software Center (now just called "Software"):
Ubuntu "Snap Store":
Now, to install a *.deb file using the GUI file manager, such as nautilus (default), or nemo (my preferred choice), simply right-click the *.deb file and go to --> Properties --> "Opens With" tab --> select "Software Install" (which is now available since you just installed gnome-software) --> and click "Set as default" --> Close.
Now you can just double-click the *.deb file in your GUI file manager to install it!
Note: you might also consider trying the gdebi package installer, as described here: Problem installing .deb in Software Install Ubuntu 20.04. Apparently, in some cases where the "Software Install" GUI option fails, and you would have to otherwise manually run sudo dpkg -i myfile.deb to install the *.deb file, the "GDebi Package Installer" GUI option works.
gnome-software and the snap-store: Ubuntu Software doesn't open in Ubuntu 20.04
Best Answer
This behavior is consistent with Ubuntu Software Centre. Canonical works with third-party software providers to provide payment and hosting for commericial software in the partner repository. In Ubuntu 16.04 LTS, this is being replaced by the Ubuntu App Store which powers the snap repository's backend.
While the command line tools provide access to free-of-charge snaps without issue, the Ubuntu Software store uses Ubuntu One to handle payment processing and order history (so that previous purchases can be downloaded and installed on any number of systems that you own).
So this is an implementation detail that matches the behavior of the software being replaced by Ubuntu Software.