Neodymium magnets will mess up the data on the disks.

Does the floppy drive work? Try with a known working floppy drive

DankEngihn wrote:

Neodymium magnets will mess up the data on the disks.

Does the floppy drive work? Try with a known working floppy drive

Yes it works, I tried 3 different floppy drives, the TDK floppy came back to life, while the verbatim still give me the same error.

Have you tried to use the diskettes in another, more modern machine? My 286 won't read my DOS 6.22 diskette, but my Windows 10 PC with a USB floppy drive can read it fine. So can my 386 laptop. If it does work in a more modern machine, I'd suggest using WinImage to back up the diskette and rewrite it. Maybe it might even be able to correct it.

I'm still using 1,44MB floppies to move files from my Win10 PC to old systems and from time to time Win10 PC will kill them, but they are perfectly good after reformatting in old PC...

Other issues like that may be caused by strong magnetic/electromagnetic fields, unstable systems (like you mentioned), failing floppy drive (it may work fine most of the time but every once in a while it may dammage the logical structure on the floppy during write).

FAMICOMASTER wrote:

Have you tried to use the diskettes in another, more modern machine? My 286 won't read my DOS 6.22 diskette, but my Windows 10 PC with a USB floppy drive can read it fine. So can my 386 laptop. If it does work in a more modern machine, I'd suggest using WinImage to back up the diskette and rewrite it. Maybe it might even be able to correct it.

I will try, but I don't care what's inside I use floppy mainly as booting device or to update bios.
The problem is that when I try to format I get the track 0 error
How can a overclocked system permanently damage 2 floppy disks? 😲

Nemo1985 wrote:

How can a overclocked system permanently damage 2 floppy disks? 😲

They may be not physically damaged, just dos refuses to format them. I had good results formatting using a completely utility, like booting some linux.

You may try unconditional formatting:

1format a: /u

It sometimes helps for disk with badsectors.

Thank you all for the advices, unlucky the Verbatim disk proved to be unrecoverable, despite all the the efforts I tried, including boot with linux :\

Try a DOS software called resqfloppy.

Also check if the disks have deep circular marks, this could mean physical damage. If they do, clean your floppy drive.

Deksor wrote:

Also check if the disks have deep circular marks, this could mean physical damage. If they do, clean your floppy drive.

Clean? I would say to just flat out replace it if it's causing physical damage to the diskettes. No reason to try and keep / repair it at that point, they're cheap enough.

No, it's not always the floppy drive to blame in case of damaged disks. Sometimes just junk on the head can turn drives into killers, and unless you buy them new, they're all susceptible to have this issue to some degree (of course many are still ok nowadays but it's still a bit of a gamble). And also sometimes it's the disk that's totally rotten in some way and is deteriorating itself against the heads of the drive, making it very dirty and thus requiring you to clean it.

Also, if you are using a USB floppy drive, don't put anything on top of it while you are using it. It took me killing 3 or 4 disks to learn that lessson.