Common Error Message.
Take the following actions for these common error messages.
The disc in the DVD-ROM drive is not High Sierra or ISO 9660 format.
The DVD-ROM drive does not support this format.
The 'not ready reading the drive' situation occurs if you try to access the
DVD-ROM drive before the drive is ready. The Busy indicator lights when
you attempt to access the drive after loading a disc into the loading tray.
Wait until the Busy indicator is no longer lit before attempting to access the drive.