In part 2, at the moment of Cooper departure from the black lodge,  Mike and The Arm points out there's something wrong. 'My doppleganger' says The Arm and we get to see a moment where Cooper sees BadCoop in his car going through a giant hole in the ground.  TheArm doppleganger says 'Nonexisting' and sends Cooper in the middle of nowhere which leads to the machine in New York. Where would Cooper be now if he had just left the lodge without The TreeDoppleganger interfeering? Who knows

I was just wondering if the problem here might emply less fantasy than theories about shoes or else.  A man that's been stuck 25 years has a memory condition related to the one a coma can cause. If this man waking up finds himself living the life of another man it's basically impossible for him to recover memory. 

End of my theory: They (Gordon &co) just need to find him in Vegas to start the process.  And i put a coin on a picture of Laura Palmer to be the starting element of recovery (He has seen her right before He leaves the lodge afterall)