Re: Unreadable CD-R ... or is it?
 

How about using disk utitlity?
I had a faulty external HD that my mac couldn't see. But on opening disk utitlity I was able to view the files and back them up.
Apps/Utilities/Disk Utility

Re: Unreadable CD-R ... or is it?
 

Nope ... Disk Utility recognises there's a disc in the drive but won't allow any operations to be performed on it.