When I run my swift 3.2 code with Xcode 9 beta 4 this is the error I get:
*** Terminating app due to uncaught exception \'com.firebase.core\', reason: \'[FIRAp
In my case something went wrong when i merged conflicts in project.pbxproj
GoogleService-Info.plist -> didn't have Target membership selected on the right pane and I couldn't select it because project.pbxproj was corrupted (even though build was successful)
I had to rollback project.pbxproj and after that GoogleService-Info.plist had Target membership selected.
Make sure project.pbxproj isn't corrupted after merging conflicts (it had something to do with attempted to initialize an object with an unknown UUID)