Recovering from optical discs
Burned discs were once regarded as a safe way to keep a backup, and many people still hold an archive of photographs, documents and backups saved that way. The problem is that the dye layer the data was burned into degrades over time — so a disc burned years ago can simply stop being readable, even when it looks perfectly intact.
Why a disc stops reading
- Scratches on the surface or on the label side
- Degradation of the dye layer over the years, known as disc rot
- Exposure to sunlight, heat or humidity
- A burn that was never completed properly in the first place
How we handle it
We read the disc in dedicated drives at low speed, with repeated re-reads of the problematic sectors, which usually extracts data an ordinary drive gives up on. Where there is physical scratching it is sometimes possible to improve readability before the attempt. Recovered files are then checked for integrity.
What you should do
If you have an archive of discs, do not wait. Copy it to a hard drive or to cloud storage while the discs still read. A disc that barely reads today may not read at all next year.