copying unity project between computers

hey guys. I am trying to copy a unity project between 2 macs, i have even tried the third one but I always run into the same problem, some of the assets get disconnected and after a while the unity crashes... its the same version of unity on all of the machines and im copying the whole thing... any suggestions ?

Are you copying the entire project folder, or just the assets folder? You need to make sure you copy the folder which contains the Assets folder and the Library folder.

I don't have any problems doing it this way and I do it very regularly, between a Mac and a PC.

If you are collaborating on a project, I would really recommend getting hold of a asset server. That helps a lot.