This is slightly off-topic, but very germane and worth repeating.
Consumer-grade CD-R and DVD-R use a vegetable-based dye which is what is "burnt" on the disc.
Those dyes have a shelf life.
It's about 6 to 10 years before use.
But, it's only about 24 to 36 months after use before data degradation starts setting in.
You really need to check discs you are relying upon about every three years, to make sure the data is still good.
Which is also complicated, as Recordable disks of 5 and six years ago, those slower 4x, 6x, 8x discs, had more 'permanent' dyes on them. So, you could have very old discs which are good, and newer ones which are not.
I've been to this game a time or two, and it is not fun. OEM discs lost in fire, and then relying upon the in-house copies, to find those copies are not so good.
Double-check your data, mes amis.