No disc, huh? Yet it shows the type of disc in the drive!
Possible cause: Started CDSpeed, with BenQ 1620 selected as the drive. Inserted disc into Samsung, and then selected Samsung drive in CDSpeed. Waited for Samsung to recognize disc, then hit "Start".
I'm guessing switching drives will the sammy was still recognizing the disc is what caused it.
Oh well...close & restart, and all is well!