I haven't changed the location of any sample libraries but still had the message pop up. Even after I locate the "missing" samples from 40s Very Own Keys and Hybrid Keys, the MIDI would still make no sound. This has happened on nearly all my projects that use those samples. I've also tried following the troubleshooting advice which tells me to repair those specific instruments on native access but none of them need repairing so idk. Any solution would be helpful.