What do you mean by 'won't open'? Can you elaborate, e.g. error message etc? Running the same MPC version on both systems? Project uses less than around 1GB ram?
There is an error, forgot to take a photo of it and don't have the unit with me now. Yes, they are both on the same release version. Well I guess some of the tracks were made in different software versions. That would cause them to not open? I would think older would always open in newer releases.