Epson EL 3S/33 - Manual (Page 90)

Diskette Problems
You see a diskette error message.
Reinsert the diskette, making sure you insert it all the way. If
the drive has a latch, turn it down to secure the diskette.
Also, check to see that you have inserted the right type of
diskette in the drive. For example, make sure you are not
inserting a high-density diskette in a double-density drive.
Reinserting the diskette does not solve the problem.
Insert the diskette in another diskette drive of the same type. If
you can read the diskette in a different drive, your drive may
be faulty.
The diskette is the right type, but you still see an error.
Check that the diskette is not write-protected, preventing the
drive from writing to the diskette.
Make sure the diskette is formatted. See your operating system
documentation for instructions on formatting diskettes.
You may have a defective diskette. Try copying the files from
the bad diskette to a new diskette.
Something is wrong with the data in the files.
If you are using DOS, use CHKDSK to repair the files. You may
also be able to use special utilities or diagnostics to solve this
problem.
6-6 Troubleshooting