Been using an Axiom 49 for about 3 years. All of a sudden the keyboard display reads "OFF" and I can't I can't change programs to get any sound. So I connected another controller in and IT DOES NOT WORK EITHER! What could be going on? What can I check? Sitting with no controller.....:( Thanks as always.

You connected another controller into... what? What's this other controller? Does the capslock keyboard work to produce sound? Look in the manual for your Axiom to see if there's a way to reset it to a factory state

I unplugged the axiom and replaced it with midi piano using a midi to usb cord. (which has worked in the past.) The capslock keyboard works. Axiom manual is worthless. I will go on utube and see if I can find something to reset axiom. Thanks Ski

Do a quick test with GarageBand. Do your MIDI Controllers work there?

If your USB Keyboard works in Garageband or another DAW then your Logic preference file may be corrupt. I had this before. My USB Keyboard worked fine in Ableton but not Logic. When deleted the preference file that corrected everything.

Before you go trashing prefs just yet... does this happen with every project or just one in particular? If it's isolated to one project then there might be a less disruptive fix available than trashing prefs.

My M-Audio USB controller just inexplicably stopped working in Logic Pro X as well. It worked fine for 2 years. I went to add a track into a song and the keyboard just stopped responding!! I am running Mavericks on a 2013 MacBook Pro. Did I change a preference or hit a button that disables my usb keyboard?? The Musical Typing keyboard popped up. That works fine but now I can't finish my project!! Please help. All the Google and YouTube stuff is for configuring a MIDI controller. Is this a simple fix?? I see these other posts are from 2009! So I am really worried.