Error when loading Ogre Sample into Unity 2019.2

Using Unity 2019.2.19f1 on Windows, Oculus Integration 12.0. When loading the sample Unity throws the following error:
Exception: Cannot load. Incorrect path: Packages/com.unity.render-pipelines.lightweight/Shaders/Autodesk Interactive/Autodesk Interactive.shadergraph Null returned.
Both the Unity installation and the path to the project have no spaces.