Microsoft KB Archive/161020

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Implementing Windows 95 Updates


The information in this article applies to:

  • Microsoft Windows 95
  • Microsoft Windows 95 OEM Service Release, versions 1.0, 2.0, 2.1, 2.5


Microsoft stands behind its Windows 95 product, and develops updates for Windows 95 as needed to resolve critical customer situations. This article provides general information about Windows 95 updates. Topics in this article include:

  • Windows 95 Update Version Information
  • Identifying Windows 95 Updates
  • The Windows 95 Update Information Tool (Qfecheck.exe)
  • Installing Windows 95 Updates on a Single Computer
  • Uninstalling Windows 95 Updates on a Single Computer
  • Installing Windows 95 Updates Using Server-Based Setup
  • Obtaining Windows 95 Updates
  • Knowledge Base Query Tips


Windows 95 Update Version Information

The version numbers of the original retail and OEM release of Windows 95 and the OEM Service Releases are listed below. In general, files included with the indicated release of Windows 95 have the indicated version stamp.

Release Version File dates
Windows 95 retail, OEM 4.00.950 7/11/95
Windows 95 retail SP1 4.00.950 0A 7/11/95
OEM Service Release 1 4.00.950A 12/31/95
OEM Service Release 2 4.00.1111* 8/24/96
OEM Service Release 2.1  4.03.1212-1214* 8/24/96-8/27/97
OEM Service Release 2.5 4.03.1214* 8/24/96-8/27/97


  • In the case of Windows 95 OEM Service Release 2 (OSR2), 2.1 (OSR 2.1) and 2.5 (OSR 2.5), not all files have this version stamp. In the case of OSR 2.1 and OSR 2.5, only files updated to provide support for the Win32 Driver Model (WDM) and Universal Serial Bus (USB) may have this version stamp (the remainder maintain the same version stamps as the corresponding OSR2 files).
  • Windows 95 OEM Service Releases are not available for download.

You can view a file's version information by using the right mouse button to click a file in Windows Explorer, clicking Properties on the menu that appears, and clicking the Version tab. If the property sheet for the file does not show a Version tab, there is no version information available for that file.

With few exceptions, Windows 95 updates are stamped with a version number of 4.00.951 or greater, indicating that the file is a newer version than originally included with Windows 95. Updates to Windows 95 OEM Service Release 2 (OSR2) generally have a version of 4.00.1112 or greater.

It is possible that multiple fixes would be applied to the same component. With a few rare exceptions, these fixes are always cumulative. A change implemented in a given version of a particular component is also included in later versions of that component, along with any additional change implemented in the later versions. (For example, version 4.00.952 would contain the change implemented in version 4.00.951, as well as the new change.)

The cumulative nature of these changes, combined with the incremented version numbers, means that, with very few exceptions, there is always one "current" version of a given component, containing all fixes made to that component to date.

Identifying Windows 95 Updates

Nearly all Windows 95 update files can be positively identified by the following two characteristics, which can be viewed on the Version tab of the property sheet for the file:

  • A version number greater than the product release version.
  • An additional string resource named "Special Build Description" that is set to the value "QFE."

Some Windows 95 files do not contain version information to identify the file. In such cases, the modified date and size of the file can be examined and compared to the original release version of the file. These are not conclusive indicators, however, because the modified date can be affected by various conditions, and changes in a file may not result in a change in the file's size.

The Windows 95 Update Information Tool (Qfecheck.exe)

The Windows 95 Update Information tool (Qfecheck.exe) is installed with each Windows 95 update. This tool uses information stored in the registry, and version and special build information in the files themselves, to identify installed Windows 95 updates. This tool can be used to identify which Windows 95 updates have been installed on a given computer.

To run the Qfecheck tool, run the Qfecheck.exe file in the Windows folder (or in some rare cases, the Windows\System folder). The tool contains online help.

For additional information about the Windows 95 Update Information tool, click the article number below to view the article in the Microsoft Knowledge Base:

Q145990 Windows 95 Update Information Tool (Qfecheck.exe)

Installing Windows 95 Updates on a Single Computer

To install a Windows 95 Update on a single computer, run the self- extracting installer. This performs the following actions:

  1. Unpack the files that are needed for installation into a temporary folder. These files typically include:

    • The updated component file(s)
    • The QFECHECK tool (Qfecheck.exe and Qfecheck.hlp)
    • An .inf file used to uninstall the update
    • An .inf file used to run the installation (W95upd.inf)
    • In some cases, Advpack.dll, W95inf16.dll, and W95inf32.dll files
  1. Use the Windows 95 built-in Setup library (Setupx.dll) or an external setup library (Advpack.dll) to install the specified update according to the directives in the provided .inf file (W95upd.inf). This .inf file contains directives to copy files to their appropriate locations, and add registry settings as appropriate. Some later installer packages may use multiple .inf files to allow a single package to install one of several different versions of an updated file, depending on the version of Windows 95 that is installed.

If a newer version of the updated component has already been installed, the older version is not installed. In most cases, this occurs silently. For some older installer packages, you may be prompted to keep or overwrite the existing component.

  1. Inform you when the update is complete and prompt you to restart the computer. When you click OK, the temporary files from step 1 are removed and the installation program terminates.

Uninstalling Windows 95 Updates on a Single Computer

In most cases, Windows 95 updates can be safely and easily uninstalled and replaced with the original versions of the updated components. This is typically facilitated by an .inf file copied to either the Windows\INF\QFE folder (in most cases), or to the Windows folder (for some older installer packages), during installation of the update. This file typically has a name of the form <xxxxx>_UN.INF. This .inf file can be used to uninstall the Windows 95 update by right-clicking the file in Windows Explorer, and then clicking Install.

When a Windows 95 update is uninstalled, you are prompted for the original Windows 95 installation disks or CD-ROM. The original version of the files are copied and overwrite the updated versions. An alternate file location may also be specified at this time. When uninstallation is complete, you typically need to restart the computer for the change to take effect.

Installing Windows 95 Updates Using Server-Based Setup

Extracting Package Contents:

Most Windows 95 update installer packages now support command-line switches that allow the contents of the package to be extracted to a specified directory, without launching the INF-driven installation routine. The command to perform this operation would be:

<path to update file>\<update filename>.EXE /C /T:<destination folder>

For example, to extract the contents of XXXXXUPD.EXE, located in C:\DOWNLOAD, to the C:\UPDATE destination folder, the command would be:


This functionality is available in Windows 95 update installer packages created after October 1996. If you are not certain whether a particular installer package supports this functionality, run the installer with a "/?" command-line switch. For example, type the following command:


If a window appears listing the available command-line switches for the package, you may use this command to extract the contents of the package to the desired destination folder. If, instead, a window appears prompting you to install the update, the installer package does not support these command-line switches, and the alternate method described below must be used to extract the contents of the package.

Referring to the steps above for installing onto a single computer, note that the files used in the installation are located in a temporary folder until you click OK in the final prompt window. During this time, the files can be copied into a different folder and saved for further use. Depending on the specific Windows 95 update being installed, this temporary folder may be one of the following folders:

  • Windows\Temp
  • The <temp> folder (as specified by the TEMP environment variable)
  • <temp>\Ixp000.tmp (as specified by the TEMP environment variable)

Copying the Files to a Network Share:

If Windows 95 workstations are being set up from a network share, the updated component files can be copied into the appropriate folder(s) on the network share before installing Windows 95 from this share. In this way, new workstations can be configured with the updated components from the very beginning.

The appropriate folder into which to copy the updated component files depends upon the type of installation.

  • If the network installation share contains only the Windows 95 .cab files, the updated component files should be copied into the same folder as the .cab files. When Windows 95 Setup copies the file from this source to the destination, it will copy standalone files from that folder, if they exist, instead of the same files from within the .cab files.
  • If the network installation share is a server-based-Setup share point created using the Netsetup tool (from the Windows 95 CD-ROM), the updated component files should be copied into the same folder as the components they replace, overwriting the original versions of those files. Note that a given file may appear in more than one folder, so be sure to update all instances of the original file.

The .inf file used to install Windows 95 updates (W95upd.inf) includes registry information that is either necessary for the update to provide the intended functionality, or is simply useful in tracking which updates have been installed. We recommend that this file be examined by the administrator, and the appropriate sections merged into the Msbatch.inf file used during Setup, to ensure that this registry information is incorporated when the update is installed.

To install Windows 95 updates on existing Windows 95 workstations that are running a shared installation of Windows 95 from a server, it is normally sufficient to update the component files in the shared folder. In very rare cases, updates to real-mode components will require the files to be copied to the individual computers, either on the server or on the workstation's local hard disk or boot floppy disk.

To install Windows 95 updates on existing Windows 95 workstations that are running local, standalone installations of Windows 95, one of the following methods can be used:

  • Network Systems-Management software. Products such as Microsoft's System Management Server can be used to automate software updates. Once the updated component files are extracted and registry updates identified, these can be distributed according to the functionality provided by such products.
  • Logon scripts. If Windows NT or NetWare logon scripts are in use, a command can be added to check whether a particular update has been installed, and launch the installer if needed. For example:

          IF NOT EXIST %WINDIR%\xxxxx_UN.INF START xxxxxUPD.EXE 
  • E-mail. The self-extracting installer can be distributed in an e-mail attachment. Upon receiving the e-mail, users would run the attached installer to install the update. The e-mail attachment could also consist of a shortcut to the installer in a shared folder on the network.
  • Intranet Web site. The self-extracting installer can be placed on an internal Web site, where users could go to install the update.

These methods are suggestions. There may be other methods not listed here that can be used to distribute these software updates.

NOTE: When the self-extracting installer is used to install the Windows 95 update, a check is made to ensure that a newer version of the component is not inadvertently overwritten with the version being installed. If an alternate installation method is used, care must be taken to prevent replacing a newer component with an older one. In some cases, replacing a newer component with an older one could render the computer unable to boot.

Obtaining Windows 95 Updates

Categorized by availability and distribution methods, Windows 95 updates fall into two primary categories: those available publicly from online sources, and those not available publicly, but only available by contacting Microsoft Technical Support. Publicly-distributed Windows 95 updates are available to be downloaded from the Microsoft Download Center. For additional information about how to download Microsoft Support files, click the article number below to view the article in the Microsoft Knowledge Base:

Q119591 How to Obtain Microsoft Support Files from Online Services

Microsoft used the most current virus detection software available on the date of posting to scan this file for viruses. Once posted, the file is housed on secure servers that prevent any unauthorized changes to the file.

To determine which file to download, query the Microsoft Knowledge Base to find the article that references the issue. Specific instructions are included in each article.

Windows 95 updates that are not publicly distributed can be obtained by contacting Microsoft Technical Support, through any of our direct support offerings, including telephone and Web response. Note that server-based Setup (using Netsetup) of Windows 95 OEM Service release 2 and 2.1 (OSR2) is not supported. OSR2 was designed to be preinstalled on new computers by computer manufacturers. One of the main components, the FAT32 file system, requires that the computer's hard disk be repartitioned. For this reason, OSR2 is not distributed to resellers.

Attempts to distribute OSR2 using Netsetup result in users being prompted for a Product ID number. This number is usually listed on the Microsoft Certificate of Authenticity. Modifying the Msbatch.inf file does not prevent this prompt.

Knowledge Base Query Tips

Information about specific Windows 95 updates and issues resolved by these updates can be found in the Microsoft Knowledge Base by querying on the issue's symptoms.

Additional query words:

Keywords : osr2 win95
Issue type : kbinfo
Technology : kbWin95search kbOPKSearch kbWin95 kbWin95OPKOSR25 kbWin95OPKOSR210

Last Reviewed: June 13, 2001
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