GFS works best with the latest graphics drivers, and in some cases, outdated drivers could cause GFS to not communicate with your graphics card and stop working.
Check if your drivers are up to date:
You should always keep your GPU drivers up to date. This not only ensures higher Space Coin production, but more importantly also improves your gaming performance.
What is NVIDIA SMI?
NVIDIA SMI (System Management Interface, or NVSMI) is a part of your drivers that GFS uses to read information about your graphics card and allows GFS to interact with it. If SMI is missing from your drivers, GFS may direct you to reinstall your drivers with the latest ones from the manufacturer.
Note about Workstation GPU's: Workstation GPUs (Tesla/Quadro/Firepro/etc) have drivers specifically geared towards 3D modelling and rendering applications. This typically makes it so that the card does not work with GFS, or does not work well. For more information, look at What graphics cards (GPUs) are / are not supported?