Game installed in external hard drive: Even though external hard drives have a very fast read/write ratio, they still tend to cause problems especially when a game is running.
Reinstalling or disabling them might be the trick in your case.
NVIDIA Sound Drivers: NVIDIA drivers (especially sound drivers) are known to cause several problems whenever an update is released.
In this case, the game either crashing or freezes randomly.
Background applications: There might be background applications which might be either conflicting with the game or competing for resources.
System Requirements: If the system requirements of StarCraft are not being met, you will definitely experience crashing issues no matter what.