The process of downloading the NVIDIA CUDA Toolkit 5.5.20 for MAC driver should begin automatically after a few seconds. If this does not occur, click on one of the links below (we recommend downloading the NVIDIA CUDA Toolkit 5.5.20 for MAC driver from the primary server - this is the manufacturer’s Nvidia official website). If the download still fails to run, check whether your anti-virus software is not blocking the connection to the manufacturer server of the NVIDIA CUDA Toolkit 5.5.20 for MAC diver.