Game "not Responding" When Loading Mission

[Birchflower]

This has happened several times now, but until today has righted itself and I was able to continue.  Today, however, when trying to load Aphrodite, the game essentially froze at about 30% loaded.  After waiting about 3 minutes, I manually shut the game down entirely.

 

Last night was experiencing lag spikes and fleeting graphics glitches.