I wanted to give you an update. I did a reset to factory settings on my computer (after backing everything up), and re-downloaded Maya and the character rigs. AND... I'm running into the same problem. I think it has to do with the character rig file itself. I'm using Malcom 2.0 from AnimSchool and every time I try do reference him in - even in a clean new shot - the program freezes. I can reference and open files with other rigs. I'm not sure why this specific rig is giving me a problem all of a sudden after having used it for so long?