Another issue to be aware of when you upgrade from F29 to F30

[Alan]

Make sure you turn off any Gnome extensions that you have downloaded
from gnome.org. There is an issue where some gnome extensions that are
loaded from the user account will cause gnome-shell to crash. What you
will see is you try to log in and after a few seconds it returns back
to the login screen. (And yes, it is a reported bug. And yes, it still
happens, because it just happened on the upgrade I am doing now.)

The way I have fixed the problem is to delete anything in
~/.local/share/gnome-shell/extensions/ and then redownload the ones you
need.

Hope that helps.