How to fix
Windows update error 0x80070420
on Windows

I can't install Windows updates because of the 0x80070420 error. I have never dealt with this before, so I would ask you to assist me with this problem. I am using Windows 11 23H2.

Windows Update is one of the critical components in a Windows system. It's where patches that fix vulnerabilities, updates that enhance performance, and additional features are provided. However, due to errors, this may not happen as expected, and error code 0x80070420 is no exception for some users. This type of error occurs mainly when one tries to download or install an update; it may show a message stating that it cannot continue with the update process.

The causes of error code 0x80070420 may vary. These, in turn, often relate to a non-active or not correctly set Windows Update service. Conflicts from third-party antivirus software or wrong settings in firewalls can also result in the failure of correct installation of updates.

Sometimes the issue arises because some system files are corrupted, while sometimes it is just because there is something wrong with the Windows Update components themselves that altogether halts or fails the updating process.

Error 0x80070420 can be fixed with several steps. The essential beginnings are to make sure that the service of Windows Update is active and its startup set to automatic. Disable third-party antivirus programs or temporary settings changes, and change firewall settings to rule out conflicts blocking the update.

Run the Windows Update Troubleshooter to detect and resolve common problems with Windows Update. This is because third-party apps can clash with updates. Therefore, if the problem does not resolve, it will be necessary to perform a Windows Update component manual reset or run a System File Checker scan that will replace damaged system files.

For those who do not want to do this or for whom that was not working, using a trustworthy [d1] repair tool will automatically start searching and repairing in-depth system conflicts that contribute to the error 0x80070420 and will make the update cycle smooth and effective.

Fix 1. Run SFC and DISM scans

Damaged system files frequently cause errors during Windows updates.

• Open Command Prompt as administrator.
• In the Command Prompt window, paste the following command and press Enter:
  sfc /scannow
• Wait for the scan to complete.
• Once the SFC scan is finished, run the following set of DISM commands, pressing Enter after each one:
  DISM /Online /Cleanup-Image /CheckHealth
  DISM /Online /Cleanup-Image /ScanHealth
  DISM /Online /Cleanup-Image /RestoreHealth
  (Note: if you get an error executing this last command, add /Source:C:\RepairSource\Windows /LimitAccess to it and try again).
• After completing the DISM commands, restart your system.

Fix 2. Employ the troubleshooter

If you haven't tried this yet, give a Windows update troubleshooter a go:

• Type Troubleshoot in Windows search and press Enter.
• Select Additional troubleshooters/Other troubleshooters.
• Find Windows Update from the list.
• Click it and select Run the troubleshooter/Run.
• Restart your computer when the update process is finished.

Fix 3. Check the relevant services

Some services, such as BITS service, for example, are mandatory for the automatic update process to be completed successfully. As such, you can try restarting these services and setting their startup to automatic.

• Type in Services in Windows search and hit Enter.
• Locate Background Intelligent Transfer Service (BITS).
• If this service is already running, right-click and select Restart.
• If it is not running, double-click it, select Automatic under the Startup type from the drop-down menu.
• Click Start, Apply, and OK.
• Repeat the process with the Windows Update, Cryptographic, and Windows Installer services.

Fix 4. Try using Media Creation Tool

Media Creation Tool by Microsoft is one of the ways to resolve deep system-level issues and update your Windows to the latest version. Make sure you uninstall third-party security software before proceeding.

• Visit the official Microsoft website and download Windows 10 installation media (Windows 11 version).
• Double-click the installer and select Yes when UAC shows up.
• Agree to terms.
• Select Upgrade this PC now and select Next.
• Windows will now download all the necessary files – it might take a while.
• Agree to terms once again and click Next.
• Before installing, make sure that you are happy with your choices (otherwise, you can click Change what to keep option).
• Click Install to begin the upgrade process.

Fix 5. Reset Windows update components

Clearing the cache and resetting other components removes corrupted files in the SoftwareDistribution folder, which may be blocking the update.

• Open Command Prompt as administrator.
• Paste each of these commands, pressing Enter after each:
  net stop bits
  net stop wuauserv
  net stop appidsvc
  net stop cryptsvc
  Del “%ALLUSERSPROFILE%\Application Data\Microsoft\Network\Downloader\*.*”
  rmdir %systemroot%\SoftwareDistribution /S /Q
  rmdir %systemroot%\system32\catroot2 /S /Q
  regsvr32.exe /s atl.dll
  regsvr32.exe /s urlmon.dll
  regsvr32.exe /s mshtml.dll
  netsh winsock reset
  netsh winsock reset proxy
  net start bits
  net start wuauserv
  net start appidsvc
  net start cryptsvc 
• Restart your PC.

Fix 6. Install the update manually

• Type Updates in Windows search and hit Enter.
• Click View update history.
• Here, note down the KB number which failed to be installed.
• Go to the official Microsoft Update Catalog website.
• Type the KB number into the search bar, and press Enter or click Search.
• You will find many different versions on the update – you need to find the one that matches your PC specs and Windows version (as a home user, ignore Windows server versions).
• Right-click on Start and pick System.
• Under Device specifications, check the System type section: it should either be 64-bit or 32-bit.
• Scroll down to Windows specifications and check the Version section.
• With all this information, pick the correct version for your device.
• Go back to the Microsoft Update catalog, download the appropriate version, and install it.