DIAGNOSIS The printer is stuck in a driver installation loop. It's waiting for a software handshake from the computer that never completes. This is a common USB setup glitch.
FIX Unplug the USB cable from both the printer and the computer. On the printer control panel, press the Home button. Navigate to Settings > General Setup > USB Host Timeout. Change the setting from 300 seconds to 0 (Infinite). Reconnect the USB cable. The message should clear and the printer will be ready.
IF THAT DIDN'T WORK The firmware may be hung. Turn the printer off. Unplug it from the wall for two full minutes. This clears the volatile memory. Plug it back in and power on. Use a different, high-quality USB cable if the problem persists.
HEADS UP If you're on a network, skip USB and set it up using the printer's IP address. It's more reliable. The 'USB Host Timeout' setting will revert to 300 seconds after a full power cycle or factory reset.