The M-Audio Radium 49 is a legacy controller that is not class-compliant, meaning it requires specific drivers to function over a USB connection. Because M-Audio has not released updated drivers for modern macOS versions, getting it to work depends entirely on which version of macOS you are running. 1. Identify Your macOS Version

Modern macOS (Catalina to Sonoma/Sequoia): There are no official drivers for current macOS versions. Users on macOS Ventura or Sonoma will find the device is not recognized when plugged in directly via USB.

There is a community-maintained project on GitHub and SourceForge that provides a 64-bit driver for legacy M-Audio devices.

• Use a known-good USB cable and try different USB ports (avoid unpowered hubs; use a direct port or a powered hub).
• If the keyboard has a dedicated power switch, power it on after connecting USB.