Manually Install MSU or CAB files

 

An .msu file contains the following contents.

Content	Description
Windows Update metadata	Describes each update package that the .msu contains
One or more .cab files	Each .cab file represents one Windows update
An .xml file	This .xml file describes the .msu update package. Used for unattended installation of the update by using the Package Manager tool (Pkgmgr.exe).
A properties file	This file contains string properties that Wusa.exe uses. For example, this file contains the title of the associated article in the Microsoft Knowledge Base.

To install an .msu update package, run Wusa.exe together with the full path of the file.
EG: if the Windows6.3-KB999777.msu file is in the C:\999777 folder, type the following command at a command prompt to install the update package:

• wusa.exe d:\999777\Windows6.3-KB999777.msu

 

If you want to expand it you can expand the .msu file to a temporary folder:

• expand -f:* "C:\999777\Windows6.3-KB999777.msu" %TEMP%

Then, you type the following command at a command prompt:

• pkgmgr.exe /n:%TEMP%\Windows6.3-KB999777.xml

OR if the package expands to a CAB file. You run the following commands to install the packages:

start /w Pkgmgr /ip /m:c:\temp\Windows6.3-KB999777-x86.cab

NOTE: Package Manager installs only the first cab found in a folder.

 

Source of this information: http://support.microsoft.com/kb/934307