Applications installed with snap from 'Ubuntu Software Center' app store fail to launch - Ubuntu 19.04

Question

Problem:

Applications Installed from the 'Ubuntu Software Center' app store, like Chromium and Visual Studio Code will not launch. Pre-installed applications like Firefox work fine. I got Chromium to work by uninstalling it from the store GUI and reinstalling it via the terminal with apt, so this leads me to think it might have something to do with snap package manager. I could theoretically install all my applications with apt from now on, but I'd like to use the app store.

Investigation:

After running "sudo tail -f /var/log/syslog" in the terminal and clicking on the Visual Studio Code Icon, it fails to launch and the terminal reports the following:

Jun  5 10:58:30 robby-zenbook gnome-shell[1716]: g_environ_setenv: assertion 'value != NULL' failed
Jun  5 10:58:30 robby-zenbook code_code.desktop[1716]: snap-confine has elevated permissions and is not confined but should be. Refusing to continue to avoid permission escalation attacks

Answer 1

For those who care, I got the applications installed from 'Ubuntu Software Center' to work by uninstalling and reinstalling snap. Here were my steps:

1. open terminal (of course)
2. $ sudo apt autoremove --purge snapd
3. $ sudo apt update
4. $ sudo apt install snapd
5. restart your computer
6. ensure snap installed correctly with $ sudo snap install hello-world and $ hello-world
7. $ sudo apt install gnome-software-plugin-snap
8. open 'Ubuntu Software Center' and click the button to install plugins and restart.

The applications downloaded from the store should now launch successfully.

Answer 2

This error will also occur if apparmor is installed on ubuntu, but not enabled or running. Solution is to run the apparmor service, or if you really don't want it, disable it. At least, enabling apparmor (systemctl enable apparmor; systemctl start apparmor) solved the problem for me on ubuntu 19.04.

Without that, every time I rebooted, the original problem reappeared (it was fixed for a single boot cycle by reinstalling snapd).