I have a quite silly problem: I imported the Vuforia 5-0-6.unitypackage as a new custom asset to a new Unity project (Unity 5.1.3 p1 personal edition, Mac OS 10.10.5 Yosemite). After choosing from the prefabs the ARcamera, I do not see at all the field for the license key in the "Vuforia Behavior script" section. Please, take a look at the attached screenshot. Therefore, I cannot build or get the camera working, neither in play mode nor on a real device.
However, in an older Unity-Vuforia test project with the same setup, it is the same (no enter field for the license key), but I can still build the complete project as app and the camera would start in play mode too.
This is really strange. Hope that someone can give advice what to do.