Learn how to fix if Windows 10 Anniversary Update failed to install and reverts to previous version, while upgrading via Media Creation Tool.
Click here to learn about Windows 10 Anniversary Update after upgrade problems.

Microsoft rolled out Windows 10 Anniversary Update (AU) few hours ago, worldwide. You can read all about this update in following article:

Windows 10 Anniversary Update Released, Download Now

Some users have reported that they were not able to install this update. Especially, those using Media Creation Tool (MCT) are receiving following error while upgrading:

Something went wrong

You can contact Microsoft support for help with this error. Here is the error code 0xa0000400.

FIX Windows 10 Anniversary Update Failed To Install

If the update fails with MCT, you can try other options to upgrade. If you’ve disabled Windows Updates, then only option left for you is to download AU‘s ISO file. But while using the AU ISO file for upgrade, we found that the upgrade will erase apps and settings on your existing edition and keep personal files only.

FIX Windows 10 Anniversary Update Failed To Install

So in this way, you have only one option and that is to make clean install with Version 1607 ISO file. But before trying that, give a shot to these suggestions:

FIX : Windows 10 Anniversary Update Failed To Install

1. If AU fails to install under Windows Updates, you can run Windows Update troubleshooter. Perhaps, resetting Windows Update components manually may also help you.

2. Try clearing pending updates (steps mentioned in FIX 2 of this article) and also try to erase the content of Windows Update (Software Distribution Folder) using steps mentioned in FIX 1 here.

3. If AU fails with restoring your previous version of Windows along with mention of either of these error messages:

  • The installation failed in the SAFE_OS phase with an error during BOOT operation
  • The installation failed in the FIRST_BOOT phase with an error during SYSPREP operation
  • The installation failed in the SAFE_OS phase with an error during INSTALL_DRIVERS operation

Then try general suggestions mentioned here: FIX 1 | FIX 2.

4. Some users have found that MCT in their case says – This tool can’t upgrade your PC – The language or edition of the version of Windows currently installed on your PC isn’t supported by this tool.

FIX Windows 10 Anniversary Update Failed To Install

This is because MCT is getting AU upgrade of different language from the Microsoft server. This is same as the case we mentioned above for AU ISO file in which you can’t retain apps and settings. So you should change your language settings plus system locale to match ISO‘s language setting. If both matches, you can upgrade and your apps and settings won’t delete. For MCT, you can try setting language to English (United Kingdom) and see if it helps.

5. Even after trying all of the suggestions, there are no changes in situation, you can go ahead with clean install of AU.

Hope something helps!

Also check: Windows 10 November Update fails to install.


  • Thanks Kapil. I’ll try the Update Troubleshooter, this evening. Nothing else here seems to match my problem / symptoms. What seems to be the case for me is that Data partition, I’ll call it partition0, it does not have a drive letter, is the default 100meg but has only 3% available. I’ve tried numerous ways to find the 97 megs occupying the drive but nothing will display them. Have you any ideas on this front?
    Thanks and Regards,

  • Kapil, I tried update troubleshooter, it found no issues, I checked the registry for keys indicating an upgrade in progress, no Joy. I think I’ve tried all your suggestions. Does anyone know what it is that fills up the first partition but cannot be seen or detected. Does anyone have an idea how to remove it.

  • Kapil Arya

    ^^ I believe that might be system reserved partition/Microsoft reserved partition. Do let me know what actually happens when you upgrade, so that I can help you further.

  • I tried downloading windows 10 anniversary twice, each time taking better than 6 hours. Both times the download goes right to the end, and then just went to “restoring previous version” with no explanation. I was so hoping that this would take care of the many issues with windows 10. Disappointed is a mild statement … I know the continued trudging along with windows 10 and all their issues is getting to be old news. Any help for an average computer user would be most appreciated.

  • Kapil Arya

    ^^ You can try downloading Windows 10 ISO (having Anniversary Update) and try upgrading using it: https://www.kapilarya.com/download-latest-windows-10-iso-files

  • If you have a Logitech wireless mouse with a little USB dongle that plugs into the computer, remove it during the install. It seems to be fixing a LOT of people’s problems. And you can remove it anytime. My laptop went immediately from black screen to 75% after it sat overnight and I found this solution. It sounds dumb, but it WORKS.

  • Kapil Arya

    ^^ Thanks for your inputs on this 😊

  • Hi Kapil ,

    Would it possible for you to let me now about windows 10 upgrade from windows 7 or windows 8.1, Am trying for last few days through WSUS but not able to, as in the R&D there was a time when few systems were detected windows update in their windows update box, but now in WSUS am receiving the client needed the windows 10 upgrade but it is not reflect on client machine after pushing , I have already setup WSUS twice .

    Please Ping me on **Email address removed for privacy** if you have any solution.
    Thanks in Advance

  • This fix finally worked!!! I’ve been failing since two months to fix it.
    Thanks a lot!

  • Kapil Arya

    ^^ Glad we could help 😎

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