This seems to happen to every project after it gets to a certain age. I click to open the master ProChannel on the console, and Sonar just hangs.
I don't have any 32-bit plugs in there, no sussppiicciiious freeware plugs either. Just an instance of Guitar Rig with a compressor, and standard ProChannel modules. That's all I use.
When it happens I know I have little chance of ever being able to open it again in the console, so I have to open it in the inspector. Not the end of the world, but pretty annoying and of course these little things just make you feel on edge about the general stability of the program when you're working with it.