03-04-2020, 09:09 AM
Yeah, it could be your disks were subjected to moisture and there is layer of mold or fungus on the surface. It seems that 3.5” disks were much more susceptible to this than 5.25” disks. You could try cleaning the disks. There are some part on Thingiverse that you can 3D print to make it easy to clean 3.5” disks.