I have a similar problem to one described here
http://yabb.jriver.com/interact/index.php?topic=89216.0 where from time to time (seems to be while listening to other files) inserting subsequent CD's are no longer recognized by media center. at this point I have no option but to exit media center and reopen it before I can continue to rip.
Any help regarding this would be appreciated!
I had considered upgrading to MC20 but this issue persists there also! ?
Are there any settings files that could safely be deleted that might be corrupted etc.?