Hi Peter, yes as others have mentioned above it's likely to be a bug in the video driver.

If you unmaximize and resize the unmaximized window does it refresh then?

You might try rolling back your video driver to the previous one and see if that does any good.

Transitioning to and from sleep mode is a pretty complex area of the operating system and it is not that unusual for there to be driver bugs in this area.

Another thing you could try is to switch the graphics interface that MoI is using. To do that go to Options > General > "Edit .ini file" button and find GraphicsAPI=Auto and set it to GraphicsAPI=OpenGL and see if you get different driver behavior.

MoI defaults to using the Direct3D11 GPU interface which usually on Windows is the most stable but possibly not on your specific hardware/driver environment.

- Michael