Various symptoms occur when attempting to view the eBook via the Bookshelf app on a Windows 10 computer or attempting to install the Bookshelf App on a Windows 10 computer.

The new version of Bookshelf has an improved and updated rendering process and it uses/requires DirectX 10 features.

Unfortunately, if the Graphics driver is not up to date, a Microsoft generic graphics driver is being used, or if it doesn't support DirectX 10, a black or grey screen will show up when viewing content.

Review the VitalSource Bookshelf Support Article to locate the appropriate Computer Vendor support details for assistance updating the graphic adapter driver here:

 https://support.vitalsource.com/hc/en-us/articles/201967663-Windows-Black-Gray-content-shown-instead-of-text

There is no additional information.