Files NOT to sync between PT usb and desktop

I've got PTB all setup on a USB but I would like tosync it to my desktop and run it from there. Each time I after copying the files to the desktop and running from there, it asks me to set up and account as if it is stating from scratch. There got to be some settings file which is causing this. anyone know which one?

I'll also want to sync back to the USB.

(And for a final thought, I'd like to sync the desktop folder with everything in it to another PC (in case I forget my USB). I actually had this setup when I first started playing with PTB. Turned out PTB had to be on the same lettered drive on both PC's.)

Thanks,
BC