UPDATES AGAIN AND FAILED

Question

2026-03 Security Update (KB5079473) (26200.8037) HOW TO FIX THIS UPDATE

Answer 1

Hi rahul thakur,
Welcome to Microsoft Q&A forum. I'm happy to help.

Your system may have corrupt files, please scan your system by following commands using Command Prompt (Run as administrator):

DISM /Online /Cleanup-Image /RestoreHealth
sfc /scannow

Please reboot your computer after the task has completed.

Then you may follow this article to troubleshoot the Windows update: Windows Update Troubleshooter - Microsoft Support.

Alternatively, you may manually download the update package to install through Microsoft Update Catalog. Just enter the KB you need to Search form then choose the package right for your system.

I hope that above information is helpful to you.

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Answer 2

Hi,

Let’s check some additional information to help you better:

1. In your search bar, type Winver and press Enter, then please share a screenshot of the result.
2. Could you list the troubleshooting steps you’ve already tried so I can avoid repeating them?

Answer 3

To fix repeated failures installing 2026-03 Security Update KB5079473 (build 26200.8037) on Windows 11, try these approaches in order.

1. Use Windows Update normally

• Go to Settings → Windows Update.
• Select Check for updates and let Windows try to download and install KB5079473 again.
• This update is designed to download and install automatically for Windows 11 24H2 and 25H2 via Windows Update and Windows Update for Business.

2. Install from Microsoft Update Catalog (manual install) If Windows Update keeps failing, install the update manually using the Microsoft Update Catalog.

A. Download the correct packages

1. Open the Microsoft Update Catalog for KB5079473.
2. Download the packages that match the device architecture:
   • x64 for most standard PCs, or
   • arm64 for ARM-based devices.

KB5079473 may require multiple MSU files in a specific order. There are two supported methods:

B. Method 1 – Install all MSU files together with DISM (recommended)

1. Create a folder, for example: C:\Packages.
2. Place all downloaded MSU files for KB5079473 into C:\Packages.
3. Open Command Prompt (Admin) or Windows PowerShell (Admin).
4. Run one of the following (replace architecture as appropriate):
   • Command Prompt (x64 example):

          DISM /Online /Add-Package /PackagePath:C:\Packages\Windows11.0-KB5079473-x64.msu
     

   • PowerShell (x64 example):

          Add-WindowsPackage -Online -PackagePath "C:\Packages\Windows11.0-KB5079473-x64.msu"
     

   • Command Prompt (arm64 example):

          DISM /Online /Add-Package /PackagePath:C:\Packages\Windows11.0-KB5079473-arm64.msu
     

   • PowerShell (arm64 example):

          Add-WindowsPackage -Online -PackagePath "C:\Packages\Windows11.0-KB5079473-arm64.msu"
     

DISM will automatically detect and install any prerequisite MSU files in that folder.

C. Method 2 – Install each MSU file individually in order If Method 1 still fails, install each package in the documented order.

For x64 devices:

1. Install:
   • windows11.0-kb5043080-x64_953449672073f8fb99badb4cc6d5d7849b9c83e8.msu
2. Then install:
   • windows11.0-kb5079473-x64_651d0cdb7665e03bb80b4c198784b255081032d2.msu

For arm64 devices:

1. Install:
   • windows11.0-kb5043080-arm64_df540a05f9b118e339c5520f4090bb5d450f090b.msu
2. Then install:
   • windows11.0-kb5079473-arm64_629cb153c8cb6b7257375994cfcf1b934a0cdafd.msu

Each MSU can be installed either by:

• DISM (Command Prompt as admin):

    DISM /Online /Add-Package /PackagePath:full-path-to-msu
  

• Or by double-clicking the .msu file to use Windows Update Standalone Installer (wusa.exe) and following the prompts.

3. If the update still fails

• Sometimes transient issues on Microsoft’s side or local servicing stack problems self-correct after some time. There is a documented case where KB5079473 initially failed with error 0x800f0991 and then installed successfully later without additional steps.
• Ensure the latest servicing stack update (SSU KB5083532) is installed; it is bundled with the latest cumulative update, so reattempting KB5079473 via Windows Update or Catalog should bring it in automatically.

4. Removing the update (if needed after partial install) If KB5079473 partially installs and causes issues and removal is required:

• Use DISM /Remove-Package with the LCU package name (found via DISM /Online /Get-Packages).
• Do not use wusa.exe /uninstall on the combined SSU+LCU package; the SSU cannot be removed once installed.

If all of the above fail repeatedly, wait a day and try again via Windows Update, as backend or catalog-side issues can be corrected by Microsoft without changes on the device.

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References:

• March 10, 2026—KB5079473 (OS Builds 26200.8037 and 26100.8037)
• March 10, 2026—KB5079473 (OS Builds 26200.8037 and 26100.8037)#Windows 11 servicing stack update (KB5083532)- 26100.8035
• March 10, 2026—KB5079473 (OS Builds 26200.8037 and 26100.8037)#Arm64 instructions
• March 10, 2026—KB5079473 (OS Builds 26200.8037 and 26100.8037)#x64 instructions
• March 10, 2026—KB5079473 (OS Builds 26200.8037 and 26100.8037)#Server Update Services
• Latest Security Update KB5079473 (26200.8037) Fails to Install - Microsoft Q&A