Microsoft KB Archive/311385

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

Article ID: 311385

Article Last Modified on 11/6/2001

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APPLIES TO


 * Microsoft Windows XP Home Edition
 * Microsoft Windows XP Professional

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This article was previously published under Q311385



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

An unexpected I/O error has occurred.



CAUSE
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 &quot;An unexpected I/O error has occurred&quot; error message.



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



MORE INFORMATION
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.

Keywords: kberrmsg kbenv kbprb KB311385

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