Solution 1 - Ensure all games are fully closed and re-start your computer
PC
1. Hold down on the CTRL ALT DELETE keys on your keyboard
2. Click on Start Task Manager
3. Locate the game(s) open in the Applications list
4. Select the game and click on End Task
5. Also locate any files with the game title in the Processes tab and click on EndTask
6. Then you can re-start your computer
Mac
1. Click on the Apple Menu located in the top left corner
2. Select Force Quit
3. In the pop up menu, select the game name and click on Force Quit
4. Then you can re-start your computer
Solution 2 - For players using dual monitors
1. First follow the above steps to ensure all games are fully closed
2. You will then need to disable your second monitor via this link!