I sometimes get a popup “Zwift Is Not Responding”, why?

Gnome (Mutter) has a standard timeout of 5 seconds in which it expects applications to respond. This is often not enough when launching heavier applications such as a game.

"Zwift" Is Not Responding

The solution is to simply extend the timeout or disable it entirely.

To extend the timeout to 1 minute (recommended):

foo@bar:~$ gsettings set org.gnome.mutter check-alive-timeout 60000

To disable the timeout entirely:

foo@bar:~$ gsettings set org.gnome.mutter check-alive-timeout 0