A year or so ago I bought a CD on eBay with a lot of scanned-in technical data. When I got it, I picked off the things I was going to need relatively soon and printed them off. All went well.

A couple of days ago I tried to load the CD and it wouldn't read. Tried it on several drives on different computers and different OS's -- same result.

I realize that it wouldn't take much, maybe a few bits melting away in the boot record or something, but I thought these things were immune from that for a lot longer than a year or two.

Recordable disc and not a printed one? Check for finger prints to start. That can throw off the drives. Gently wipe the reading surface with a soft cotton lintless cloth.

I think the discs are sensitive to light (and heat) especially strong sunlight (inks degenerate). Don't know how you've been storing the disc since you got it.

Printed CDs can rot is the seal breaks and the metal oxidises.

Also if cleaning the recorded side of a CD always use a lintless cloth and only make straight wipes from the center hub to the edge (think "wiping spokes on a bicycle tire".) CDs are expected to have some spurious bit errors and there is a good error correction algorithm to handle that. The data are written as one continuous spiral and if you wipe it in a circular motion it increases the odds that multiple bits in a row could become damaged rendering the ECC useless.

Correct.

I'll try the cleaning technique and see what happens.

OTOH, I know a lot of people just routinely record stuff on CD-R's, so this is like a wake up call to me (and presumably them).

CDs deteriorate depending on the financial status of the the country and the interest rate, along with the inflation rate......oh wait not that kind.

Mostly scratches make this happen.

I think the polymers in CD-Rs degrade over time. I have heard that 5 years is a safe upper bound, beyond that you start risking bit errors which could lead to losing information.

Discs do deteriorate over time, as noted a couple years ago in https://www.flyertalk.com/forum/showthread.php?t=558872, but I agree that one year seems too short.

While CD-Rs and DVD�RWs are not a filewrite-and-forget medium, one can appreciate their durability if old enough to remember cassette tapes and floppy disks. I remember the stern admonitions in elementary school never to leave those Apple IIe 5�" floppies next to a phone, lest the magnets wipe not just your Oregon Trail game, but your Lemonade Stand as well.

"Perfect sound forever" - CD sound was always far from perfect and now we know the physical medium is far from "forever".

See http://www.luminous-landscape.com/tu.../hd-back.shtml for a note at the bottom - 3 of 100 discs failed in 3-6 years. And those were on quality discs from someone worried about archiving.

Before I read up on media, I went and bought free-after-rebate cakes of disks from the local office supply house. Once I learned, and downloaded tools to check P0 and PI error rates, and found just-burned disks with error rates near the limits (250-300). Buying quality media (TY), this came down to single digits.

I doubt an ebay seller is to worried about media quality, and I use to have the occasional coaster (unreadable right after a successful burn), so failure after 1 year is very possible.

(I now keep all of my photos on 2 sets of optical disks and 2 archive hard drives - 1 set in my safe, 1 set at my in-laws 200 miles away)

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I have had many of my early music cds that I burned go bad in just a couple of years. This was pretty low-quality media, but I imagine even better stuff will have problems over time.

Same scenerio here. Once I saved a bunch of vacation photos from various years onto the CD-R media (with no other backup), and the CD died on me. I was so sad.

It was a live and learn thing, and I know not to do that again (or at least I'll make sure to have backup of backup now)

I remember a PC Magazine article from 2 decades back. Seems the U.S. military was testing floppies by blowing a small nuclear device (or some radiation source) over a B-52 hull with some floppies. The floppies survived the radiation fine but what got them was heat (which weakens magnets and that's what floppies and hard drives are).

As for CD-R(Ws) and DVD+/-R(W)s, they are an ink which does decay overtime. I have some Fuji DVD+Rs which claim 100 year life but I wouldn't bet a penny on that.

Big discussion on this some years ago. For "pressed" Cd the best advice is store in case on edge. Should last decades. Very high heat/humidity can cause a commercial CD to fail (delamination, mostly) but this is rare.
OTOH, a "burned" CD can fail easily if you expose it to high temperature and/or very bright light. Sunlight inside a car is an example. This can make your CD/R unreadable very fast. You have to keep these at a reasonable temperature, which, in my experience, is the biggest cause of failure of this media. Scratches are obviously bad, too, but I am always careful in handling anything and this is hardly ever my issue. I've had some CD/R's fail that have been left in a computer for weeks and apparently got too hot. Always try a "failed" CD/R in a couple other players if you can---you might be surprised. One player's failure might work on another---this has happened to me often enough.

Even archive quality CDRs stored optimally (in cool and dark place) can fail in under 10 years. I had some recorded in 1999 that started having errors this year (checked once a year for viability). And these were special CDR media (Verbatim super dye) that costs 20x the normal CDR price, so really best case. I seriously doubt that any CDRs will survive 30 years, and most fail before 5 years. DVD+R lasts much longer than CD-R (estimated 100 year life) due to a different recording technique and better error correction (not true of DVD-R). Moral of the story: copy any CDRs that you want to keep onto fresh CD-R media every 3 years, or copy to DVD+R.

Fuji does make some DVD+Rs that actually do last 100 years (their normal DVD+R is 30-50 year life). They don't claim 100 years for their CD-R or DVD-R media. If you are serious about this stuff, check out Taiyo Yuden media (sold in Japan under the That's brand name, available in US on some TDK brand lines as well as others).

I take these claims with a grain of salt as DVD's have only been around for 13 years, and the current formulation have only been around for a couple of years. I've been involved in enough "simulations" to be cautious. If "forever" turned out to be 5-10 years, I'm concerned about what 100 years might turn out to be.

As mentioned above, I agree that TY media, non-printable, is the best out there today. I mark them only on the internal plastic ring, not on the back opposite the burned surface. I'll probably re-burn them every 5-10 years, although I suspect that copying to new formats may be faster than that. I'll probably be able to transfer to archival grade Blu-ray in 2-3 years.