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I have a burned audio CD that I'm trying to rip using iTunes on a recent vintage iMac (with a slot loading SuperDrive).

I was able to import about two-thirds of the tracks before the inserted disc started spinning more noisily in the drive. (eventually sounded like very fast consecutive "swoosh"ing noises.) This spinning got gradually slower until it stopped altogether, and the progress of the import matched this slowdown and halt. At this point, you can hear the laser head seeking back and forth, but as the disc isn't spinning, no data is read.

After stopping the import of the CD and ejecting it, the drive rejects the disk outright upon reinsertion. What could be causing this behavior? Is it possible for burned CDs to break down, or for data read from the disc to cause the drive to spin down?

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up vote 1 down vote accepted

Aha, figured it out on my own:

The CD as it spins in the drive is heating up and expanding, but unevenly. This may be due to the full-disc-printed-sticker-labels that were are attached to one side of the disc by the author, and are not expanding at the same rate, or perhaps a manufacturing defect in the disc itself.

Since one side expands faster that the other side of the disc, it becomes cone-shaped and the drive spins it down when it realizes it's not a flat disc anymore.

After the deformation the disc is not immediately readable, however if you let it cool down and reform it will be readable again, at least briefly.

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Have you tried other CDs? It almost sounds more like the drive is failing or failed. The data being read cannot cause the drive's RPM to change, aside from slight speed changes depending on where on the disc it is reading. It is possible the disc is defective and binding the drive somehow, but since it was successfully burned by another computer, I find that unlikely.

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The drive is good, and the behavior is replicable on other hardware. What could be causing the disc to go bad in the middle of reading from it? – NReilingh Feb 24 '11 at 20:48
Interesting. It's possible that if the disc has gotten warped and is binding against the drive mechanism, it could cause it to fail in roughly the same spot each time. I have never heard of bad data causing it though. That's something that in every case I've seen simply throws an error of some sort, but the drive keeps spinning anytime it's happened to me. – BBlake Feb 24 '11 at 21:20

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