"Disk I/O Error: Status = 00000001" error message occurs when you start the computer

This article was previously published under Q317050
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SYMPTOMS
When you start your Microsoft Windows NT 4.0-based computer, you may receive the following error message:
OS Loader v4.01
Disk I/O Error: Status 00000001

Windows NT could not start because the following file is missing or corrupt:
%SystemRoot%\System32\Ntoskrnl.exe

Please reinstall a copy of this file.
CAUSE
This behavior may occur if any one of the following conditions is true:
  • You install Windows NT on a partition that is larger than 7.8 gigabytes (GB) or you use a third-party disk partitioning utility to expand the size of the system partition.
  • You apply either a service pack or another software update that replaces Windows system files, and the files that are required to start Windows, such as the Ntldr, Ntdetect.com, Ntoskrnl.exe, or Boot.ini files, are placed outside the first 7.8 GB of the hard disk. For example, this problem may occur after you install the security update that is described in the following Microsoft Security Bulletin:
For additional information about the 7.8-GB system partition limit in Windows NT, click the following article number to view the article in the Microsoft Knowledge Base:
224526 Windows NT 4.0 supports maximum of 7.8-GB system partition
RESOLUTION
To resolve this behavior:
  1. Repartition the system partition so that it is less than 7.8 GB.
  2. Perform a clean installation of the operating system, and then install updates.
  3. Restore the data from a backup file if necessary.
WORKAROUND
If you have to gain access to the computer to back up the data before you repartition the system partition, follow these steps:
  1. Create a Windows NT boot disk.

    For additional information about how to create a Windows NT boot disk, click the following article number to view the article in the Microsoft Knowledge Base:
    301680 How to create a boot disk for an NTFS or FAT partition in windows
  2. Copy the Windows 2000 versions of the Ntldr and Ntdetect.com files to the boot disk, and then restart your computer with the boot disk to gain access to the computer and to back up the data.
  3. Follow the procedure that is mentioned in the "Resolution" section.
MORE INFORMATION
The behavior that is described in the "Symptoms" section may also occur if any one of the following conditions is true:
  • The Default value in the [Boot Loader] section of the Boot.ini file is either missing or invalid.
  • Windows NT is not installed in the location that is specified in the Boot.ini file.
For additional information about how to troubleshoot the error message described in the Symptoms section of this article, click the article numbers below to view the articles in the Microsoft Knowledge Base:
124550 Err Msg: Windows NT Could Not Start...Ntoskrnl.exe
270862 OFF2000: Error Message: OS Loader V4.01 Disk I/O Error Stats=00000001
For additional information about disk partitioning and limitations, click the following article numbers to view the articles in the Microsoft Knowledge Base:
114841 Windows NT boot process and hard disk constraints
197295 Windows NT does not boot to a partition that starts more than 4 GB into disk
119497 Boot partition created during setup limited to 4 gigabytes
154052 Explanation of x86 boot drive limitations
Properties

Article ID: 317050 - Last Review: 12/07/2015 08:48:18 - Revision: 2.2

Microsoft Windows NT Server 4.0, Terminal Server Edition, Microsoft Windows NT Server 4.0 Standard Edition, Microsoft Windows NT Workstation 4.0 Developer Edition

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