My instrument list is broken

The only options are piccolo, treble flute, and something called E, as well as all of the MDL drumline instruments. I've uninstalled and reinstalled musecore multiple times, and the instruments XML file seems fine to me. I'd like to be able to write for more than just battery, and I've tried everything i can think of. no one else has posted having similar problems, as far as I can tell.

On a possibly unrelated note, musescore crashes everytime I press z.