Ubuntu 18.04: cannot locate the core or legacy core snap

I think I probably closed a snapcraft cli without exiting first on my ubuntu 18.04 computer. After that it would only restart with me in some wierd snap environment. After screwing around with grub I got the computer restarting properly and I uninstalled all snap apps and snap.

Then I installed snap and firefox. When I try to run firefox I get this error.

cannot locate the core or legacy core snap (current symlink missing?): No such file or directory

Did you remove snapd in the process?

How did you ‘uninstall all snap apps and snap’, and what was the output when you ‘installed snap and firefox’?

OK, I’m back online. To keep it short…

Since this issue began I have had at last one sudo apt upgrade

I just did sudo snap install firefox
Firefox installed and is now working.

Thanks to all for your help. I’m really excited about snap!