Epson Equity 286 PLUS - Manual (Page 230)

9.
If you see one of these messages, make sure the diskette is
properly inserted in the drive. On a 5 1/4-inch diskette drive,
make sure the drive latch is closed. Try the operation again.
If the problem persists, try removing the diskette and
reinserting it. This may solve the problem if the diskette was
not seated properly in the drive.
If the error message still occurs, you may have a defective
diskette. Use the MS-DOS COPY command to copy the
files from the bad diskette to a new diskette. (See your
MS-DOS Reference Manual for instructions.)
If you see no error messages but there is something wrong
with the data in a file, MS-DOS or an application program
may have updated the storage information on the diskette
incorrectly. This is probably the case if you have one of
these problems:
Part of a file is missing
A file includes parts of other files
An expected output file is missing.
To make the necessary repairs, use the MS-DOS program
CHKDSK. See your MS-DOS Reference Manual for
instructions.
Diskette Drive Problems
If you see an error message or have difficulty with a diskette
drive, check the following:
1. If you are having problems with a new diskette drive that
your dealer installed for you, consult your dealer about the
problem.
Troubleshotting D-11