Did a clean install of Kubutnu 18.04 on my primary PC today and I was happily going along installing snaps and generally having a good time until I installed ZSH and made it my primary shell. That’s when I crossed over to the Twilight Zone. The shell install was innocuous enough and I added OhMyZSH easily. But once I rebooted all installed snaps vanished from my Launcher. Tracing it back to the ZSH install, I reverted my terminals to using bash again and when I rebooted, I could no longer log in. So, I nuked and repaved but this time I did not install ZSH and all is behaving as expected.