Is it possible to silently run the Vista installation package for MSI 4.5?

Our friends at InstallAware had some questions on issues we have yet to answer in the beta MSI.CHM. One of these questions was:

Is it possible to silently run the Vista installation package for MSI 4.5?


Fair question. I didn't get that documentation updated for the beta. I'll enter a doc bug for the MSDN topic "Windows Installer Redistributables" at

The .MSU file format is a new package type for Windows Vista (and above) which contain updates to the Windows platform. These .MSU packages have an executable called wusa.exe to which you can pass command line switches. This separate EXE method is similar to the way msiexec.exe is the runtime for.msi packages. The wusa.exe is more formally known as the Windows Update Stand-alone Installer.

There are two KB articles for how to work with the Windows Update Stand-alone Installer. These are

The need for KB 929761 is something we found late in testing and are still investigating our options.

With the new Vista specific packaging technology, the old instructions for how to defer the reboot also needs to be updated. When the new .MSU packages are processed, the Transacted File System (TxF at is used. One of the qualities of the Windows Update Stand-alone Installer use of TxF is that if any file is in use, the entire update is deferred until after reboot. Given the Windows Shell often has Windows Installer loaded, we expect this means that applying the Windows Installer 4.5 Beta on Vista will often require reboots.

We do have reboot reduction work planned for after Beta. We are conscious that most users find one reboot difficult to manage and more than one reboot baffling. This presents an opportunity for chainers to provide high quality reboot management.

[Author: Robert Flaming]
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Comments (4)

  1. zhakim says:


    An indication that the KB is not installed installed is receiving error code 34 from the command line call KB935695.MSU /quiet

  2. zhakim says:


    When troubleshooting wusa, it helps to look at the WindowsUpdate.log in the windows directory.

    When troubleshooting the .MSU file, it helps to look at the CBS.log in the windowslogscbs directory.

  3. The first public beta version of the Windows Installer (MSI) 4.5 runtime, SDK and documentation has just

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