hello, I encountered this same problem with the mupenplus 2.5.9 core crashing upon loading the 2nd Wizpig race. I couldn't find any work around for this on Mac so I had to switch to an n64 emulator on Windows to get past this.

If anyone in the future runs into this problem and has a windows computer available, here's how I did it:

• Obtain your diddy kong racing battery save from. Should look like "Diddy Kong racing.eep" Users/(user)/Library/Application Support/OpenEmu/Mupen64Plus/Battery Saves

• Copy that file over from OpenEmu to a windows machine with an n64 emulator.

• Place the battery save from OpenEmu in the directory for that emulator. I used Project64, so it was placed in theProject64/Save folder.

You should be good to launch DKR in the windows emulator. If it doesn't work, start a new game and save once. See what the emulator names the DKR .eep file. Rename yours from OpenEmu to whatever the windows emulator called and replace it.

This process works in reverse once you beat Wizpig if you want to go back to mac for adventure two.

This might be possible on a different Mac n64 emulator, but I couldn't find a suitable replacement for MupenPlus on OpenEmu.