I have the same error and I have tried the 2019.1.7f version and still not working. The error is “Assets\TobiiXR\External\Providers\Vive\ViveProvider.cs(8,7): error CS0246: The type or namespace name ‘ViveSR’ could not be found (are you missing a using directive or an assembly reference?)” I have all installed and I have the Eye calibration done in the Steam VR Home so It’s working well but I can’t use it in Unity. I also have tested in newer versions of Unity and still not working.