Interestingly all my earlier floppies work no problem. The latter ones must have been poor quality and these are the ones that I continually have probs with. I copy the images of important disks to the Amiga and then put on CD. I do keep them also on the hard drive and in my Amiga Repository. All my disks are in disk boxes even the ones from the original software boxes. Dry and dust free. Also never use in dodgy drives. I have literally thousands of floppies and still find them generally reliable. More likely a drive problem when floppies start to fall over. Never give up on a disk by the way use disksalv or similar to retrieve what you can.
scuzz
http://www.commodore-amiga-retro.com
