Fix Windows 10 Upgrade error 0xa0000400

While upgrading to any version of Windows 10 using the Windows 10 Upgrade Assistant or Windows 10 Media Creation Tool, some people may encounter an error code 0xa0000400. It becomes important for a user to keep their computer up to date with all the updates, and imperative that he fix this issue.

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

There is no particular cause that has been found for this issue, but we do have some potential workaround and fix this error. We will be discussing them all in this article.

Windows 10 Upgrade error 0xa0000400

Windows 10 Upgrade error 0xa0000400

We will be discussing the following fixes to get rid of error 0xa0000400 for Windows 10 Upgrades:

  1. Use Disk Cleanup.
  2. Get the official ISO files.
  3. Turn off the Internet connections at a specific time.
  4. Get a newer version of Media Creation Tool.
  5. Run Windows Update Troubleshooter.

1] Use Disk Cleanup

Some residual junk system files like Cache files and driver residue can block an upgrade. Hence, I would recommend you to run Disk Cleanup to delete the files and data that is safe to be removed from your computer. The main files that you need to remove here should be Previous Windows Installations.

You can also use third party software like CCleaner to clean up System and Registry junk that might be causing a conflict.

2] Get the official ISO files

The best way to upgrade to Windows 10 without encountering this error would be to get the official ISO files for Windows 10’s latest release. And then you can use this ISO to upgrade to the latest version of Windows 10.

3] Turn off the Internet connections at a specific time

This workaround is tricky. What you can do is, when the update is downloaded using the upgrade tool that you are using, you can just disconnect the Internet connection.

This is fine because all the files needed would be already downloaded safely and the tool will now only be responsible for installing the newer updates using those files.

4] Get a newer version of Media Creation Tool

You can also get and use the latest version of the Media Creation Tool and check if that fixes your issues.

5] Run Windows Update Troubleshooter

You can also try to fix this issue by running the Windows Update troubleshooter.

Did these fixes help you?

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Ayush has been a Windows enthusiast since the day he got his first PC with Windows 98SE. He is an active Windows Insider since Day 1 and is now a Windows Insider MVP. He has been testing pre-release services on his Windows 10 PC, Lumia, and Android devices.