Forum Discussion

Gordony's avatar
Gordony
Iron Contributor
Feb 03, 2026

What should one do if the Windows 11 update fails to install?

Windows 11updates (including upgrading to 25H2) fail with an error after downloading and installing less than one-third of the way, and success is never achieved. How can this be resolved?

deployment
device management

3 Replies

  • ElaineLuria's avatar
    ElaineLuria
    Iron Contributor
    Feb 08, 2026

    Update failures in Windows 11, especially during major upgrades like moving to version 25H2, can be caused by various issues such as corrupted system files, outdated drivers, insufficient disk space, or lingering Windows Update components.

  • KapilArya's avatar
    KapilArya
    MVP
    Feb 05, 2026

    Hello,

     

    You can try manual upgrade using Windows 11 25H2 ISO file.

     

    Follow these steps: 

     

    Download Windows 11 25H2 ISO from the official Microsoft website.

     

    Double click on it to mount it to a DVD drive.

     

    Then go to DVD drive, double click on setup.exe to proceed. 

     

    Follow on-screen instructions to complete upgrade.

     

    For detailed instructions, refer this step-by-step guide:

     

    https://www.kapilarya.com/how-to-upgrade-to-windows-11-version-25h2#method-3-upgrade-to-windows-11-25h2-using-iso-file

     

    Let us know if this helps!

     

    Note: Included link in this reply refers to blog post by a trusted Microsoft MVP.