AutoCAD Inventor :: Locks Up For Several Minutes When Altering Assembly

I have an assembly I've been working on for a while. It was fine until after opening it one day, any changes I make cause inventor to freeze up for several minutes before completing whatever it is that I was trying to accomplish. Most of the changes are with constraints (adding parts and constraining them or changing constraints that were already in place), but I even tried to just rotate a part and Inventor locked up. I'll get the green loading bar at the bottom right corner, and it will run through a couple of times before it stops. The freezing seems to be tied to this assembly only, but I'm trying to find any other way to fix the problem before having to completely restart the assembly. I've worked with bigger assemblies before and have never run into this problem.