Canon PRO-100S series Online Manual page 535

1001
Cause
There is no disc tray.
Action
When printing on printable discs (BD/DVD/CD, etc.), use the disc tray supplied with this printer ("K" is on
the upper side). Place a printable disc on the disc tray, attach the disc tray to the printer, then press the
printer's RESUME/CANCEL button.
535