Fdisk Does Not Recognize Full Size of Hard Disks Larger than 64 GB

When you use Fdisk.exe to partition a hard disk that is larger than 64 GB (64 gigabytes, or 68,719,476,736 bytes) in size, Fdisk does not report the correct size of the hard disk.

The size that Fdisk reports is the full size of the hard disk minus 64 GB. For example, if the physical drive is 70.3 GB (75,484,122,112 bytes) in size, Fdisk reports the drive as being 6.3 GB (6,764,579,840 bytes) in size.

Fdisk uses some 16-bit values internally to calculate the size of the drive. Some of these variables overflow when the drive size is equal to or larger than 64 GB.

A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem.

To resolve this problem immediately, download the fix by clicking the download link later in this article or contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

NOTE: This hotfix is not designed for 48-bit logical block addressing (LBA) hard disks, and it is not supported on hard disks larger than 137 GB.

The English version of this fix should have the following file attributes or later: NOTE: The package that installs this fix contains both Windows 98 and Windows 98 Second Edition versions of the fix. The package automatically installs the correct version.

The following files are available for download from the Microsoft Download Center:
For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base: Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

This problem was corrected in Microsoft Windows Millennium Edition.

This package installs the updated Fdisk.exe to the Windows\Command and Windows\Options\Cabs folders, on a computer running Windows 98 or Windows 98 Second Edition. If you are starting a computer from a Windows 98 Startup Disk in order to partition and format the hard disk, you should copy the updated Fdisk.exe from the Windows\Command folder to the Startup Disk, replacing the original Windows 98 or Windows 98 Second Edition version of Fdisk.exe on the Startup Disk.

For additional information on issues with hard drives larger than 64GB, click the article number below to view the article in the Microsoft Knowledge Base: There is no fix available for any version of Windows 95. For additional information, please see the following article in the Microsoft Knowledge Base: For additional information about Windows 98 and Windows 98 Second Edition hotfixes, click the article number below to view the article in the Microsoft Knowledge Base: