Microsoft KB Archive/151581

= Cannot Upgrade Windows 95 to Windows NT Workstation 4.0 =

Article ID: 151581

Article Last Modified on 11/15/2006

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APPLIES TO


 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows 95

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This article was previously published under Q151581





SUMMARY
You can automatically upgrade to Windows NT Workstation version 4.0 from MS-DOS version 6.x, Windows or Windows for Workgroups version 3.x, or Windows NT Workstation version 3.x. If you install Windows NT Workstation 4.0 in the same folder as your existing installation of Windows or Windows for Workgroups 3.x, your existing installation of Windows is preserved so you can dual-boot between both versions.

However, you cannot upgrade to Windows NT Workstation 4.0 from Windows 95. In addition, you cannot install Windows NT Workstation 4.0 in the same folder as an existing Windows 95 installation. To install Windows NT Workstation 4.0 on a computer running Windows 95, you must install it in a new folder. After doing so, you can dual-boot Windows 95 and Windows NT, but you must reinstall your Windows-based programs for them to function properly in Windows NT. In addition, any custom settings that are present in Windows 95 will not be present in Windows NT.

The inability to upgrade an existing Windows 95 installation is a known limitation of Windows NT Workstation 4.0 that will be addressed in a later version of Windows NT Workstation.



MORE INFORMATION
There are two primary reasons that Windows NT Workstation 4.0 cannot upgrade Windows 95:


 * The registry structure is not identical in Windows 95 and Windows NT Workstation 4.0. This causes many programs to store settings in one location when you install the program in Windows 95 and store the settings in a different location when you install the program in Windows NT. Therefore, when you install Windows NT Workstation 4.0 over Windows 95, the Windows NT Setup program is unable to transfer the settings from the Windows 95 registry to the Windows NT registry.
 * The Windows NT Workstation 4.0 Setup program cannot determine which devices Windows NT Workstation 4.0 does not support. In addition, Windows 95 supports more devices than Windows NT Workstation 4.0, so it is possible for a device that is not supported by Windows NT Workstation 4.0 to be installed and functioning properly in Windows 95.

Because the Setup program cannot determine which devices Windows NT Workstation 4.0 does not support, it cannot prevent the installation process from proceeding on a computer that contains an unsupported device. This may cause the installation process to fail, or may cause the device to fail or other problems to arise after the installation process is finished.

To install Windows NT Workstation 4.0 on a computer running Windows 95, follow these steps:


 * 1) Check to see if the devices installed in your computer and the programs that you currently use in Windows 95 are supported by Windows NT Workstation 4.0.
 * 2) Install Windows NT Workstation 4.0 in a new folder, and then verify that you are able to successfully dual-boot between Windows NT and Windows 95. Note that installing Windows NT Workstation on the same drive on which Windows 95 is installed is not recommended.
 * 3) Reinstall any Windows-based programs that you want to use in Windows NT Workstation 4.0. If the program you are reinstalling has separate Windows 95 and Windows NT versions, be sure to install the Windows NT version of the program instead of reinstalling the Windows 95 version. The Windows NT version of the program should not be installed in the same folder in which the Windows 95 version is installed.
 * 4) If you do not want to run Windows 95 after installing Windows NT Workstation 4.0, manually remove the Windows 95 folder.

Keywords: kbfaq kbprb kbsetup KB151581

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