Mi4(i) Google Launcher Error!

Jan 24, 2014
Hello all,

I am having a issue with trying to use ''google now''
Everytime i want to use google now i get this error:

System Launcher is currently your default launcher. To try the Google Now launcher, go to setting touch Clear Defaults, and press the home button.

But when i want to try to do that, the clear defaults is not pressable, (light gray)

How to fix this?