Sony PCG-GRX580P - Manual (Page 156)

My floppy disk drive (optional) cannot write to a floppy disk.
 Check that the optional, external floppy disk drive is properly connected to your notebook. See Connecting an
External Floppy Disk Drive for more information.
 If the floppy disk is write-protected, disable the write-protect feature or use a floppy disk that is not
write-protected.
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