I have found some old DVD-Rs on which I had burnt pictures of trips, etc. They are of different makes and essentially all work but 4, and all of these 4 are branded MAGIK. Although they are old, they are only lightly scratched - and some of the other non-MAGIK DVDs (which do work) are much more scratched - so I doubt that's the reason.
I have tried them on my HP Pavilion laptop (I use Mint), on my laptop's Windows partition (where they are recognised but as blank, which they definitely are not), on another two older HP laptops, on an older Acer laptop and on a HP desktop I have at work [all these other 2 laptops + the desktop use Ubuntu].
Is it just a compatibility problem between the MAGIK DVDs and the CD/DVD drives I used? If so, are there specific drives known to read these DVDs?
Any help would be appreciated!