Fix Windows 10 Upgrade error 0xa0000400 [Windows 10 Update Assistant]

While upgrading Windows 10 to its latest Windows 10 May Update 2019 build using Windows 10 Update Assistant app, many users face “Something went wrong. You can contact Microsoft support for help with this error, here is the error code 0x0000400”.

This error appears while you try to upgrade your Windows using Upgrade Assistant or Windows 10 Media creation tool. Some users also face “This PC Can’t be upgraded to Windows 10 (May Update, version 1903)” or this error is also known as “What needs your attention”. This error won’t harm your computer because it’s very general but your Windows performance might get harm.

Fix Windows 10 Upgrade error 0xa0000400

To fix this error you need to try different troubleshoots until you get rid of this Windows 10 0x0000400 error. To fix this error just follow the instruction below.

Method 1: Use Disk Cleanup

Its recommended using disk cleanup to delete all the junkie data from your Windows because some time junk files or cache create many kinds of problems.


To use the disk cleanup, right-click on your Local Disk (C:) and select properties. In General, tab click on Disk Clean-Up. Here select the files to delete and click on Clean up system files.

Learn more: Are you out of storage space on your computer? Check this get disk space quickly guide and follow the Step-3.

Method 2: At the specific time turn of your internet

When the Windows 10 May Update 2019 upgrade is downloaded via Upgrade Assistant, at that point turn of your internet and see if the problem is fixed or not.

Method 3: Use Latest version of Media Creation Tool

The latest version of everything is more powerful as compared to the old version because of latest version released with new features, bug fixes and more compatible with your Windows. Download the latest version of Media Creation Tool and try again and see the problem is fixed or not.

Method 4: Windows 10 official ISO file

The best way to upgrade your Windows to the latest version is to use official ISO file but the best way is not the always best because clean install Windows 10 is more powerful but using this you will lose your data.

Doing all the steps and get rid of your problem, let us know which method works for you through comments below.


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