"An Unexpected I/O Error Has Occurred" Error Message When You Try to Create an MS-DOS Startup Disk

When you try to create an MS-DOS startup disk, you may receive the following error message:

This issue can occur if you try to create an MS-DOS startup disk with an unformatted floppy disk. When Windows XP creates an MS-DOS startup disk, the Format utility tries to write to existing sectors on the floppy disk, and because an unformatted disk does not have a data structure, the Format utility generates the "An unexpected I/O error has occurred" error message.

To resolve this issue, format the floppy disk before you try to use it to create an MS-DOS startup disk.

To create an MS-DOS startup disk in Windows XP, insert a formatted floppy disk into the floppy disk drive, double-click My Computer, right-click your floppy disk drive, click Format, click Create an MS-DOS startup disk, and then click Start.