Where's that sysex I loaded and why the error sometimes?

I update my synths all the time with the MPC (OS updates, new patches). If you are loading midi type 0 files with embedded sysex the MPC automatically places the sysex in channel 17. So if you go looking for it, that's where it is.

The MPC can also be picky about what is needed inside the midi file, so if you attempt to load a midi file and get a error, it's typically missing some header info such as Tempo and other small stuff. I usually manually place the info in there using Midi File Disassembler/Assembler, but you may find it easier to open the file in any software sequencer and just resave it.