How to fix
Windows update error 0x800F0840
on Windows

What is error 0x800F0840 and how do I fix it? I got this while trying to install the latest security updates yesterday. It does not seem to go away by itself.

Some of the common problems that arise when the system is trying to install new updates are Windows Update errors. One such error code is 0x800F0840, which usually arises when the mechanism of update faces failure due to a conflict in the system or incomplete installation files.

This prevents the user from continuing with the download and complete installation of crucial updates and may render the operating system vulnerable to any potential security threat or failure of improving some crucial features.

0x800F0840 error is often caused by corrupt system files or conflicts with previous Windows updates. It may also occur due to issues with Windows Update components, such as when they are incorrectly configured or when the system has outdated drivers. Network issues or disruptions during the update process can also result in this error, particularly if the connection drops while downloading or verifying update packages.

To resolve the 0x800F0840 error, users generally need to reset the Windows Update components, run troubleshooting tools, or manually install updates. Repairing system files and ensuring that all pending updates are correctly applied can also address the error. In some cases, users may need to reset their network settings or clear update caches to bypass the problem.

For those seeking a faster and more efficient way to handle system-related issues, using a reliable [d1] repair tool can help detect and fix underlying problems that contribute to errors like 0x800F0840, ensuring a smooth update process and keeping the system up to date.

Fix 1. Run Windows update and network troubleshooters

• Type Troubleshoot in Windows search and hit Enter.
• Select Additional troubleshooters/Other troubleshooters.
• Find Windows Update from the list and click Run the troubleshooter/Run.
• The troubleshooter will automatically scan your system for potential problems and display any issues it finds.
• If the troubleshooter finds any issues, it will provide recommended solutions.
• Repeat this process with Network & internet troubleshooter.

Fix 2. Perform Disk Cleanup

• Type Disk Cleanup in Windows search and hit Enter.
• If your Windows is installed on drive C, pick it from the list (should be by default) and press OK.
• Click Clean up system files.
• Select your main drive again and click OK.
• Here, select the largest portions of the data used - these typically include Temporary Internet Files, Windows Update, Temporary Files, Recycle Bin, Delivery Optimization Files, and others. Marking Windows Update is vital here.
• Click OK - the process should be finished shortly.

Fix 3. Repair corrupted files

• Type cmd in Windows search bar.
• Right-click on the Command Prompt result and select Run as administrator.
• Click Yes when prompted by User Account Control.
• Then, copy and paste the following command, pressing Enter after:
  sfc /scannow
• Wait till the scan is finished. If Windows finds system file integrity violations, it will attempt to fix them. After this, use the set of the following commands, pressing Enter each time:
  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).
• Close down the Command Prompt and restart your computer.

Fix 4. Check the services

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

Fix 5. Reset Windows update components

• Open Command Prompt as administrator.
• Stop the Windows Update-related services by running the following commands one at a time, pressing Enter after each one:
  net stop wuauserv
  net stop cryptSvc
  net stop bits
  net stop msiserver
• Rename the SoftwareDistribution and Catroot2 folders by running the following commands:
  ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
  ren C:\Windows\System32\catroot2 Catroot2.old
  Note: If your Windows installation is not on the C drive, replace "C" with the appropriate drive letter.
• Restart the Windows Update-related services by running the following commands:
  net start wuauserv
  net start cryptSvc
  net start bits
  net start msiserver
• Reboot your system.

Fix 6. Install the update manually

• Type in Updates in Windows search and press Enter.
• Select View update history.
• Find the update that failed with the 0x800F0840 error and copy its KB number.
• Open your browser and go to Microsoft Update Catalog.
• Within the search bar, type in the KB number and click Search.
• Find the correct version of the update for your operating system (to check this, right-click on Start and pick System. Under Device specifications and check the System type) and click Download.
• Use on-screen guidelines to finish the installation process and restart your computer.

Fix 7. Use Media Creation Tool

If none of the above methods help, you can always use the Media Creation Tool to repair Windows and bring it to the latest version.

• 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 the terms once again and click Next.
• Before installing, ensure you are happy with your choices (otherwise, you can click the Change what to keep option).
• Click Install to begin the upgrade process.