These two story crashes I can recreate on different computers and happens everytime I do it these problems do not happen in motionbuilder 2010.

1. Merge in your Characterized character with namespace
2. create a character track in story mode and assign it to the character
3. reference in animation clip onto character track right click insert animation file
4. Razor animation clip and overlap the two clips
5. right click on one of the animation clips --change media file with a new animation clip
6. drag the time indicator over the overlapping animation clips, BAMM crash!!

if this did not crash for you then try this one

1. Merge in your Characterized character with namespace
2. create a character track in story mode and assign it to the character
3. reference in animation clip onto character track right click insert animation file
4. right click on animation clip --Make Clip Writable (I noticed some clips dont have this option, why is that?)
5. not that clip is writable, razor clip, BAMM crash!!

-all of the animation clip fbx’s that where referenced in where created with the same character

Sorry for the up

For the second crash, I have same. My character has some Character Extensions with markers with Custom Properties set on Animate
These custom porperties are causing the crash.