Having a PostProcessVolume enabled in a map will cause the app to crash on launch. Even if nothing is on within the volume, if the volume itself is enabled, it causes the crash.
OH SNAPS I FIGURED IT OUT. The post process volume crashes because I have a function that sets a DoF value on Scale, but the Scale variable is disabled in the PP volume. I just disabled that function and everything runs fine, no more crash.
I hate everything but also love it.