What is the MSU file? How to download the MSU Windows Update file? How to open the MSU file? What are the differences between the MSU file and CAB file? If you are looking for the answers, this post is what you need.

What Is MSU File

MSU files are update packages used by Windows Update. It contains one or more updates for applications and files on Windows systems. MSU files are installed by the Windows Update Standalone Installer (Wusa.exe) and run automatically by Windows Update.

Each MSU file contains four elements:

  • Windows update metadata, which describes the update package.
  • One or more CAB files that store package update data.
  • An XML file describing the contents of the MSU file.
  • Properties file read by Wusa.exe.

Tip: If you want to get some information about the Windows update, you can go to the MiniTool official website.

How to Open MSU File

How to open the MSU file? You can double-click the MSU file to launch it. If your file association settings are correct, it means that the application that opened your .msu file will open it. You may need to download or purchase the correct app. It’s also possible that you have the correct application on your PC, but the .msu file isn’t yet associated with it.

How to Manually Download MSU Windows Update File

How to download the MSU Windows Update file? Microsoft releases security updates and patches in the CAB (Windows cabinet) file format. This is the format in which your computer receives updates from the Microsoft Update server or your local WSUS server.

For easier manual distribution of individual updates using the Microsoft Update Catalog, these CAB files are packaged in a special MSU format (Microsoft Update Standalone Installer Package).

You can download MSU Windows Update files (sometimes CAB files) or files for other Microsoft products from the Microsoft Update Catalog (https://www.catalog.update.microsoft.com/). Go to the Microsoft Update Catalog to find and download the updates you need.

How to Install Windows Update from MSU File

To start the installation of a Windows update package, just double-click the MSU file you have downloaded. If the update applies to this computer, a Windows Update Standalone Installer window will open, where you will be prompted to confirm the update installation.

You can also install the MSU update package from the command line using the wusa.exe tool.

To install the update in silent mode with a delayed restart, open the command prompt as administrator and run the following command:

wusa.exe c:\Temp\windows10-22h2-kb5026435.msu /quiet /norestart


Tip: To avoid system corruption caused by the upgrade failure or the computer cannot start, you can back up the system to another hard drive in advance. But how to back up the operating system to another hard drive quickly and safely? Here is a piece of professional and powerful backup software – MiniTool ShadowMaker. You can back up the operating system, disk, partition, files, and folders with this program.

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How to Extract a CAB File from an MSU Update Package

If the Windows Update service (wuausrv) is not working correctly, you will not be able to install the update from the MSU file. In this case, you can manually unpack the MSU package, extract the CAB update file from it, and manually install it on Windows.

To extract the MUS package into the C:\Temp\kb5026435 folder, run this command (you have to create this folder in advance):

expand -f:* “C:\Temp\windows10.0-5026435-x64.msu” C:\Temp\kb5026435


What are the differences between MSU files and CAB files? A CAB file is an archive that supports several compression formats. They work with various Windows installation engines. These include the Setup API, device installer, or advpack.dll.

MSU files more or less install themselves thanks to the standalone update installers included with the Windows operating system. But double-clicking a CAB file will automatically get you nowhere. You must invoke the correct mount engine, or otherwise access its contents.

Final Words

What is the MSU file? How to download the MSU Windows Update file? How to open the MSU file? What are the differences between the MSU file and CAB file? The answers are included in the above content. I hope that this post can be useful to you.

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