I too just had this problem on my new 24" iMac. The SuperDrive DVD drive used to work fine, but then started to eject DVDs with no user interface warning. This was when I tried to install the new version of Microsoft Office 2008 from it's install DVD. I read a bunch of hints and help ideas, and tried this idea, first start up the application "DVD Player", then insert the DVD into the iMac. This then helps the Mac OS detect the DVD, even though it is not a DVD movie disc. I was then able to close the application DVD Player, and use the Finder to run the installer successfully. Hope this helps someone.
I am just about to have my SECOND superdrive replaced! The first one just swallowed any disc you fed it, and the replacement drive started out by spitting every disc out and now it is a swallower too! So freaking annoying that I have to totally dismantle my set up and cut all my cable ties, plus not have my puter for a week with no real guarantee that I wont be taking it in again in a fortnights time. Surely this is not a hardware issue...? My first Mac purchase has been bitterly disappointing! I have a silver Intel 20" iMac running Leopard (No boot camp - NO windows)
It all started yesterday. There was a CD stuck in the drive that just didn't want to come out. I tried ejecting it through iTunes - no luck. I tried ejecting it through my desktop - no luck. I tried ejecting it with my keyboard - no luck. I finally had to reboot and right when the Mac started booting back up I held the eject button down on the keyboard and the CD finally ejected.
Now today, I have the opposite problem - any CD or DVD I put in the drive is immediately ejected. It is making NO attempt to even read the CDs - it just spits them back out. I tried rebooting and it didn't help. In fact, I've tried everything I can think of to keep the CDs in the drive (even holding my hand over the opening but as soon as I take my hand away it spits it back out). I'm at my wit's end.
I'm using a Mac OSX V10.4.11 with a 1.83 GHz Intel Core Duo.
I have another MacBook running 10.5.2 that i have just burnt a test cd-r on...get this it opens fine on the other MacBook and the iMac both running 10.5.2. It appears that none of these machines will open anything burnt pre 10.5.2, but the iMac still won't recognise blank cd-r or DVD+RW. It has gotta be a software issue hasn't it?