Garageband MIDI not working at all

I just got it working again: did most of the stuff on this thread and now it's working. I hope resetting the preferences doesn't screw me up later: If GarageBand isn't working on your Mac - Apple Support

I've ran into the same thing. Since the update November 6, 2023 when I use my guitar synth to MIDI interface creates signal though all the soft synths seem "off". When I hit a note "two" notes show and it's as if a sustain pedal is on. I've also checked cables and made sure things were properly plugged in. Nothing has changed except the update and I hope they get this fixed.

Just want to support and amplify this post. GB auto-upgraded to 10.4.9 on my Mac mini last night, and it is now completely broken - same behavior as LegoPilot mentions. Just purchased the mini (M2) 2-3 weeks ago and GB was working flawlessly with my Yamaha KX88 until today. Would really appreciate some help or a bug fix release from Apple.

Same thing here. GarageBand auto-updated a little while ago and my M-Audio Axiom 61 started playing notes on pushing and releasing a key.

I've downloaded a MIDI monitoring app where I could check what signals my laptop recieved, and the monitor app showed the correct note being pressed and released, and I've checked with an older version of GarageBand on one of my other laptops and it works perfectly there, so I'm reasonably sure it's not with the keyboard.

It'd be great to get a fix!

Well done and thank you very much, Baddadio. I ran the "defaults delete com.apple.garageband10" command from the terminal, rebooted, and this fixed the issue for me as well. Really appreciate you posting here.

I did not do the full reboot though I did the "delete/reinstall" by dragging the app into the trash and reinstalling from the app store. This is after updating the drivers and bending over backwards. I also see that there's an update literally an hour ago... though I'm back. Peace to you all.

Make sure to tell Apple so they are aware of it:

Product Feedback - Apple

I have this same exact problem. I just discovered it and it's driving me crazy! Glad I'm not the only one. Hope there's a fix soon.

Same here, I hope someone finds a fix. None of the things I've tried has worked so far. Same thing, MIDI is registering a sound on the release of the key.