I'm creating my firs VR app i unity for google cardboard. I noticed VR support setting in the inspector. I searched a little bit and it isn't clear for me if I should enable it for google cardboard. Here is the link for unity manual about it. Thanks for help!
For a while you should not enable VR support since Unity has no native support for Cardboard yet, although it was announced on Vision Summit 2016 for future versions.
By now, you should only use the Unity package with the appropriated prefabs for Google Cardboard available at https://developers.google.com/vr/unity/download.