File Extensions Help

Unable to Extract Contents of MSU

The following Windows Vista updates are distributed through Microsoft Update Standalone Package (MSU) package:

• Security updates
• Critical updates
• Updates
• Update rollups
• Hotfixes

When you expand an MSU file a .cab file is extracted from it. This .cab file uses the Intra-Package Delta (IPD) compression technology. The IPD technology helps in reducing the size of the MSU file you download and still ensures that a self-contained package containing the updated files is delivered to the user. This .cab file that is compressed using the IP technology is referred to as an "IPD-aware" package.

It is not possible to extract or view IP-aware .cab files from any other program or tools used in earlier Window operating systems. For instance, you cannot extract or view the IPD-aware package files in the Windows Explorer or by using the Expand command of earlier Windows operating systems, or the third-party tools WinZip.

This is the reason why you may face problems when:

• In the Windows Vista Command Prompt window, you try to use the /x command-line switch to extract a file, command-line MSU help dialog box opens.
• You are unable to open the file on a Non-Windows Vista PC and you are prompted to locate the program in which the file was created.

Cause of the Problem

These problems occur because:

• MSU packages are can not be extracted using the /x command-line switch.
• The file extension for the Windows Vista MSU packages is not recognized by earlier Windows versions.

Resolution Steps

To resolve this issue, use the Windows Vista Expand command to extract and to view the files contained in an MSU.

Note: The Windows VistaExpand command is different from the Expand command in earlier Windows versions.

If you want to use the Windows Vista Expand command to expand the files from the MSU, perform the following steps:

1. To extract files from a hotfix package, do the following:
1. Navigate to the Hotfix.exe file and then double-click on it.
2. In the displayed Microsoft Self-Extractor dialog box, select Continue.
3. Type C:\MSUFolder, in the Select the folder where you want to unzip the files to box, and then select OK.
   
Note : If you are extracting some another package and not a hotfix package, then first create the C:\MSUFolder folder and then save the MSU file to this folder.
 
2. Now, open the Command Prompt window, type the commands listed below, and then press Enter to execute each command:

c:
cd c:\MSUFolder
expand -F:* FileName_Of_ Saved_MSU.msu c:\MSUFolder
expand -F:* FileName_Of_ Saved_MSU.cab c:\MSUFolder

When you run these commands, one or more folders are added to the C:\MSUFolder containing files with “.mum” and “.manifest” file name extensions. The added subfolders contain files that MSU updates. These files describe:

• File operations
• Registry changes
• Other miscellaneous operations that must be completed to install the component

Additional Information: Windows Vista Expand command

Syntax for the Windows Vista Expand commands:

Expand [-r] Source Destination
Expand -r Source [Destination]
Expand -D Source.cab [F:Files]
Expand Source.cab -F:Files Destination

Where,

• -r switch enables you to rename the expanded files.
• -D switch enables you to list the files in the source file.
• Source is used to specify the path and the name of the source file. You may have to use wildcard characters, such as “*” here.
• -F:Files specifies the file name that you need to expand from the .cab file.
• Destination is used to specify the path and the name of destination directory or file. Here, Source specifies multiple files and if you are not using –r then Destination is a directory.