MPC Studio Projects Missing Files

I transferred all my sounds (kicks, snares, samples, hi-hats, etc.) to my external hard drive to save space. These sounds were in one folder on my Mac. So I had no "sounds" on my Mac, but then transferred all these sounds back onto my Mac. But now, my MPC Projects are missing all these files and I cannot play any of my projects. All my projects show which "sounds" are in the project and still have the notes as they were but I just cannot listen to any of these projects because the sounds aren't in the proper location I'm assuming. Any help with this? Much appreciated.

The sounds, sequence and programs for a project must be stored in the associated project folder along with the xpj file - to fix the project, simply put the files back in the project folder.

Odd. All my samples are copied in the project folder automatically. So I could delete the original audio and the project would still be fine