CrossOver prints this warning message if it fails to create a window and an OpenGL rendering context for it. This will prevent you from using any OpenGL or Direct3D application, including most games but also applications such as Microsoft Office 2016. If you do not plan to use games or any other 3D application you can ignore this warning.
This problem is usually caused by missing OpenGL libraries or a missing 3D acceleration driver. Please consult your distribution's documentation for instructions on how to install OpenGL and 3D drivers. A good CrossOver-independent OpenGL test is the 'glxgears' tool. Also you should be able to run native Linux 3D games like tuxracer or BZflag before attempting to run 3D applications with CrossOver.
If you have a 64-bit Linux distribution, please make sure that you have the 32-bit compatibility libraries installed. You can follow our instructions for getting the OpenGL library installed.
If you think you received this warning even though your OpenGL installation is correct, please contact our support team.