Fix: Error 0xa0000400 Media Creation Tool or Update Assistant Windows 10

10 ways for how to fix Error 0xa0000400 when upgrading via either Media Creation Tool or Windows 10 Update Assistant.

Error 0xa0000400

Microsoft, two times a year comes up with major update for Windows 10 with modern features and important improvements. Unfortunately, sometimes you cannot install them because of error 0xa0000400. Users come across this code while installing the latest Windows 10 update that restricts the progress at a certain percentile. The message that appears with this problem is “Something went wrong, You can contact Microsoft support for help with this error. Here is the error code 0xa0000400”.

Most users found complaining error 0xa0000400 when they upgrade the OS via Windows 10 Media Creation Tool or Windows 10 Upgrade Assistant. The definite reason that triggers this issue is quite unknown, it may be caused by buggy files released by Microsoft. However, some experts dug out the accumulation of unnecessary junk in the disk or running a few background applications like Skype as possible causes. Here is the method list with quick links for your swift navigating to them –

Error 0xa0000400 Media Creation Tool or Upgrade Assistant Windows 10

Here is how to fix Error 0xa0000400 Media Creation Tool or Upgrade Assistant Windows 10 –

1] Run the Windows Update Troubleshooter

Update errors are pretty common in Windows 10 and many users are deprived of installing the latest Operating System features. To resolve this problem, Microsoft introduced its built-in fixit tool called Windows Update Troubleshooter. This can quickly identify the problems causing the trouble and guide you with the steps to carry out for eliminating the error. You can run this tool and fix Error 0xa0000400 Windows 10 using below guidelines –

  1. Press Windows key and I together and let Settings app appear.
  2. From the UI, click Update & Security.
  3. When the additional settings page unfolds, choose Troubleshoot from left pane.
  4. Go the right pane and select Additional troubleshooters link.
  5. Click Windows Update from the next page and also choose Run the Troubleshooter.
  6. Once the tool finds any trouble, it will show up tasks for you to complete. Follow the recommendations till the end.

2] Remove external peripherals connected to computer

External Hardware peripherals like digital camera, mouse, keyboard, joystick, gamepad, and similar stuff can often unintentionally disturb the updating process. This happens when an unexpected conflict between the software of an accessory and the system and results in blocking various newer tasks such as Windows Update. Several reports indicate that update Error 0xa0000400 Windows 10 is resolved just by removing the hardware accessories temporarily from the computer.

Remove the accessories with USB cables with care and Restart the devices after a while. In the next Windows session, try installing the updates again to check whether it is resolved.

3] Disconnect the Internet connection at a certain time

Once the files for Windows 10 Update are downloaded, some potential bugs from the internet may corrupt them. For this reason, you may experience update Error 0xa0000400 Windows 10 which is resolved easily by removing the connection. This seems a little unusual and tricky but very much effective resolution in terms of potentiality as many users have done the same for getting out the error. The method is preferable when you install the update using ISO file. To continue doing this, follow the below steps –

  1. Download the ISO file for the most recent update and make it bootable.
  2. Click on the Network icon lying on the right area of Taskbar.
  3. Select the running network and click Disconnect. If ethernet is connection is active then simply pull out the cable from port.

4] Close the Skype prior installing update

Some users have revealed the secret behind update Error 0xa0000400 Windows 10 and it’s quite surprising that Skype is halting the process. The hotfix found to be working is just to end the task of this application and related processes before starting to install the updates. To accomplish the task, follow the below steps –

  1. Make a right-click anywhere on the Taskbar empty field and choose Task Manager.
  2. When the app opens, switch to Processes tab.
  3. Reach out to Skype and right click on it.
  4. Select End task from context menu.

5] Install the Update files manually

Because Windows Update is automatic process in Windows 10 hence the recent releases are immediately installed after being available. You only need to ensure an active internet connection with the computer. The trouble is, often this automatic feature fails to install the updates hence, you need to proceed manually for that. Here are the instructions to complete the task –

  1. Visit the webpage for Microsoft Update Catalog webpage on a web browser.
  2. In the Search box, type the KB number you are looking to download.
  3. Click the Search button beside the bar.
  4. Click the Download button on the desired one compatible with device specification.
  5. Once the downloading ends up, double click the file to install the update patch following the guidelines.

You can check the patches here too – Windows 10 Cumulative Updates List.

6] Run System maintenance to fix update Error 0xa0000400 Windows 10

Damaged system files are one of the most probable reasons for which you may get the update Error 0xa0000400 Windows 10. Tracing out these files are really critical and you cannot succeed completely unless using the System Maintenance tool. This default utility locates the damaged files in the system and fixes them easily. It will also trace out and clear up as well as non-essential files causing trouble. To carry out this workaround, follow the below guidelines –

  1. Open the Taskbar Search pressing Win+Q hotkeys at once.
  2. Type Control Panel in the given text box here.
  3. Press Enter.
  4. Click Troubleshooting on the control panel.
  5. From the succeeding window, click View all from the left pane.
  6. In the newly opened page, move out for System Maintenance and click it.
  7. Click Next button from the following screen.
  8. Wait patiently until the process detects issues and then fix them automatically.
  9. Once done, restart Windows 10.
  10. Go to Settings => Update & Security => Windows update and click on Check for updates.

7] Download the Official ISO files for Windows 10 update

If you are getting update Error 0xa0000400 Windows 10 even after carrying out the above workarounds, try downloading the official ISO files. You need to create a bootable installation media with Media Creation Tool. For that, the steps are as follows –

  1. Click this link and download the Windows Media Creation Tool file.
  2. Right click on the downloaded file and choose Run as Administrator.
  3. When the UAC will prompt for permission, click Yes to proceed ahead.
  4. Hit the Accept button.
  5. From next, select Upgrade this PC now option and then Next to proceed.
  6. Hold on until Windows is ready to download.
  7. Click the Upgrade this PC now option followed by tapping Next to step ahead.
  8. Select Download and install Updates and then hit Next.
  9. Click change what to keep.
  10. Next, choose Keep your personal files and apps option.
  11. Click Next and follow the guidelines displayed to complete the process.
  12. Finally, restart the computer and try updating the Windows 10.

See – Download Latest Windows 10 2004 ISO Image File [x64, x32].

8] Clean up the junk files and make free space in the disk

Residual junk similar to cache, temporary file, Previous Windows update, software leftovers in the disk consumes space in it. These junk files also restrict the system from downloading new updates and you may experience update error 0xa0000400 Windows 10. Disk Cleanup tool is the handiest utility for cleaning such kink files in bulk amount. Here is how to use the tool –

  1. Press Windows logo, type cleanmgr and then hold down Enter key.
  2. The tool will automatically scan the installation disk and show you a wizard in a while.
  3. Click Clean up system files.
  4. From the next popup window, select C: again and press Enter key as well.
  5. In the next window named Disk Cleanup for (C:), check all the options sitting under Files to delete section.
  6. Click OK.
  7. Once a confirmation dialog “Are you sure you want to permanently delete these files” appears, select Yes.

9] Carry out Driver Updating in Windows 10

Driver controls the communication and interaction between the windows and connected external devices. Every single function in computer requires a driver and these are the most essential components in Windows. Outdated drivers make the system unstable and less powerful so they can often produce trouble in installing update. Eventually, you may get error 0xa0000400 Windows 10. To update the drivers, you can use the default Device Manager where outdated drivers are indicated with identification marks. Here are the steps to complete –

  1. Open the Power user menu by pressing “Win+X” hotkey at once.
  2. Choose Device Manager from the appearing list.
  3. When the app will open up in a separate window, look carefully in the console for any mark of exclamation.
  4. Double click the same and expand the drivers’ list.
  5. Right click the driver with a yellow indication.
  6. Select Update Driver option from context menu.
  7. On the consequent wizard, click Search automatically for updated driver software option. Make sure the device preserves an active internet connection for downloading the latest driver.
  8. When the downloading finishes, installation will take place automatically.
  9. Complete the same procedure for all outdated drivers.
  10. Finally restart the computer and try installing the updates in the following session.

10] Try Resetting the Updates

One of the most successful ways to resolve Error 0xa0000400 Media Creation Tool or Upgrade Assistant Windows 10 is resetting the Windows Updates manually. Some codes work perfectly for purging the cache. Follow the instructions –

  1. Press the Windows key and type cmd.
  2. When the Command Prompt will arrive in the result, Choose Run as Administrator option from the right flyout.
  3. Click Yes to give consent when UAC prompts.
  4. After getting access to the command prompt window, enter below texts one after another and press enter each time –

net stop bits
net stop wuauserv
net stop appidsvc
net stop cryptsvc

  1. Once done, enter these commands –

Del "%ALLUSERSPROFILE%\Application Data\Microsoft\Network\Downloader\*.*"

  • Press Enter key to delete all the qmgr*.dat files produced by BITS from the system.
  • Enter Y to confirm deletion.
  • Now, execute the below commands –

rmdir %systemroot%\SoftwareDistribution /S /Q

rmdir %systemroot%\system32\catroot2 /S /Q

Important – In this step, you might get an error message like  “The process cannot access the file because it is being used by another process.” It may happen because of restarting one of the “Background Intelligent Transfer Service (BITS)”, “Windows Update service”, furthermore “Cryptographic service”. Therefore, repeat the same method as before to stop these services again.

  1. You have to reset the BITS moreover Windows Update services to their default security descriptor now and for this, enter below commands –



  • Press Enter key.
  • Next is to open the System32 folder and for this, execute the following command –

cd /d %windir%\system32

  • For re-registering all the corresponding BITS and Windows Update DLL files on the Registry, enter the underneath tools and execute them by pressing Enter key –

regsvr32.exe /s atl.dll
regsvr32.exe /s urlmon.dll
regsvr32.exe /s mshtml.dll
regsvr32.exe /s shdocvw.dll
regsvr32.exe /s browseui.dll
regsvr32.exe /s jscript.dll
regsvr32.exe /s vbscript.dll
regsvr32.exe /s scrrun.dll
regsvr32.exe /s msxml.dll
regsvr32.exe /s msxml3.dll
regsvr32.exe /s msxml6.dll
regsvr32.exe /s actxprxy.dll
regsvr32.exe /s softpub.dll
regsvr32.exe /s wintrust.dll
regsvr32.exe /s dssenh.dll
regsvr32.exe /s rsaenh.dll
regsvr32.exe /s gpkcsp.dll
regsvr32.exe /s sccbase.dll
regsvr32.exe /s slbcsp.dll
regsvr32.exe /s cryptdlg.dll
regsvr32.exe /s oleaut32.dll
regsvr32.exe /s ole32.dll
regsvr32.exe /s shell32.dll
regsvr32.exe /s initpki.dll
regsvr32.exe /s wuapi.dll
regsvr32.exe /s wuaueng.dll
regsvr32.exe /s wuaueng1.dll
regsvr32.exe /s wucltui.dll
regsvr32.exe /s wups.dll
regsvr32.exe /s wups2.dll
regsvr32.exe /s wuweb.dll
regsvr32.exe /s qmgr.dll
regsvr32.exe /s qmgrprxy.dll
regsvr32.exe /s wucltux.dll
regsvr32.exe /s muweb.dll
regsvr32.exe /s wuwebv.dll

Important –  For registering the .DLL files, we have used regsvr32 is a command-line tool /S in order to execute the commands silently without getting any additional texts on display.

  1. Next task is to reset the network configurations and for that, execute the below commands –

netsh winsock reset
netsh winsock reset proxy

  • Finally, start the BITS, Windows Update, and Cryptographic services you have stopped previously using the below commands –

net start bits
net start wuauserv
net start appidsvc
net start cryptsvc

  • Hit Enter key after each for executing them.
  • Once done, exit the Command Prompt and reboot your computer.

1] Run the Windows Update Troubleshooter
2] Remove external peripherals connected to computer
3] Disconnect the Internet connection at a certain time
4] Close the Skype prior installing update
5] Install the Update files manually
6] Run System maintenance
7] Download the Official ISO files for Windows 10 update
8] Clean up the junk files and make free space in the disk
9] Carry out Driver Update
10] Reset Updates

That’s all!!

Sharing is caring    Share Whatsapp

Topics:  Windows
About Nipu
Windows 11, 10 Tweaker, and Tech Enthusiast.