External CD drive--not working on new mac

I've been using an external cd drive on my older macbook pro for quite awhile. I recently purchased a new macbook pro, and the external cd drive will not work--I can't see the drive anywhere. It still works on the old macbook pro. I've double checked my preferences for external drives, looked in disk utilities to see if it shows up there--all to no avail. It's obviously not the cd drive or its connection. This is the first macbook I've owned with the thunderports---and I'm using an adapter (Apple). Not sure if it's just not going to work with an adapter? Thanks for any ideas!!