The drive may be fine if you clean the heads. Some old floppies just disintegrate like that.
Edit: And since you're expecting misalinged heads, don't try any adjustments unless you really know what you're doing. Just clean the heads carefully or with a cleaning disk.

Just clean the heads. The disk failed due to shedding and should be thrown away. There's nothing mechanically wrong with the drives.

Do not try to use the drives to read any other disks until you clean them. The oxide build up on the heads can damage the disk surface

jhandsel wrote on 2021-07-01, 13:28:

I've got a Mitsubishi MF504C high density drive that was working perfectly until I tried to install a game off an old diskette. […]
Show full quote

I've got a Mitsubishi MF504C high density drive that was working perfectly until I tried to install a game off an old diskette. The diskette looked normal, but after I inserted it the drive made a loud rubbing noise, as if the heads were clamped too tightly on the disk's surface while it was spinning.

Thinking that the drive had developed a problem since I last used it, I put the same floppy into another drive and I got the same loud rubbing noise. Now neither of them will read any floppy! The drives just spin and I get the standard Abort/Retry/Fail message. Sometimes I can cd into the drive and see the contents, but the drive won't read anything larger than a single-line text file. I haven't managed to diagnose what the damage is — hopefully just misaligned heads, but I can't rule out permanent damage 🙁

This is really weird as nothing looked wrong with the game floppy (pics attached). On closer inspection there are striations on the disk's surface as if it had indeed been clamped too tightly, but I've no idea why this would happen.

Has anyone seen this happen before?

Yep, exactly the same thing happened to my IBM AT floppy drive. It was working fine, then I tried a Karateka floppy on 5.25", heard a horrible grinding and saw the rings on the disk. Cleaned up the drive heads with swabs and isopropyl alcohol ... then it ruined my previously working Gato disk 🙁 both original game floppies too so doubly sad. Further cleaning and testing resulted in a bunch of scratched and ruined blank floppies.

In my case I plan to replace the drive, so proceed with caution even if you do clean the heads.

I hope it's just a question of cleaning the heads, but if so they must be pretty badly encrusted. Cleaning with a Q-tip soaked in IPA isn't making any difference.

IPA evaporates quickly so you need to gently soak the head surface where the read head lines are for a bit. Then gently with drier IPA q-tips gently wipe off.
One quirk with old floppies is that they can get some dust inside the plastic sleeve or the oxide flakes off which can be like sandpaper to the heads and ruin them quickly on old drives....

Could it possible be mold in the floppy disk ?

I find it ironic the disk that kills drives is called "Life and Death II"

Grem Five wrote on 2021-07-02, 00:46:

I find it ironic the disk that kills drives is called "Life and Death II"

I know right, it’s pretty funny.

Anyway thanks for your advice everyone.

I cleaned the heads much more thoroughly with IPA again, and the drive is back to working condition. After swabbing with a q-tip, I also put a drop of IPA on a thin strip of white paper, gently clamped it between the heads and pulled it out, to simulate a cleaning floppy.

I’ll definitely be more careful about putting a shedding or dusty floppy in my drives in future.

Hey, congrats! 😃 Happy you got it working again.👍