Unable to Select Units or the Next Turn Button

Units can't be selected, the Next Turn button can't be clicked, or other issues related to mouse control.

Workaround:

1. Open Civilization V's config.ini file in Notepad or another text editor. 
   • This file can typically be found here on Windows: My Documents\My Games\Sid Meier's Civilization 5 (the full path is usually C:\Users\[your username]\Documents\my games\Sid Meier's Civilization 5\config.ini)
2. Find the line that says “EnableGameCoreThreading = 1" 
3. Change this to say "EnableGameCoreThreading = 0" and save the file.

NOTE: Editing game files can have unintended effects. If you notice issues after editing the file, fully uninstall and reinstall the game.