I downloaded vuforia-unity-6-0-117 this morning and imported into Unity 5.4.1p1.
I had just started a new project and made a new database with a new target. I set up everything per the https://library.vuforia.com/articles/Solution/Compiling-a-Simple-Unity-Project documentation but my webcam never finds the target; none of the 3D elements in the scene ever display.
I started with a new project and imported a database for a previous project that worked well with the 32 bit version of the Vuforia Unity extension and experienced the same result, or rather the same lack of result.
Has anyone else had problems with these two versions of Vuforia and Unity?
Being an idiot I had neglected to perform the Adding Dataset load to camera step. Works now.