MK1 - Sysex Receive hangs unit

Hi there. I have a mk1 and I’m trying to restore a project sysex dump. I sent project A1 to Sysex Librarian on my Mac. Seems to work? It says it received 466 messages at 53.2KB.

I set the Mono to Project A2, press Func + Pgm Rcv, hit Play in Sysex Librarian, it starts to chug and then the Mono goes blank except for the Follow light. At this point it’s hosed and the only way out is to power cycle it.

Any ideas?

(I know I can copy project to project on the unit itself but I’m trying to back up my work to my Mac in case something goes wrong.)