Sometimes when trying to download and install updates on your Windows 11 PC, you may run into Error code: 0x800b0109 along with an error message stating 'Some Update Files Aren't Signed Correctly'.

It occurs when there's an issue during a Windows update. It means that some of the update files don't have the proper digital signatures, which can lead to problems with the update process.

When this error occurs, Windows will stop completing the update process, whether they are security updates or cumulative updates, and the process fails. Luckily, there are several methods to resolve this problem. If one solution doesn't work, don't worry; you can try the next one because each of them is effective in various scenarios.

Causes of Windows 11 Update Error 0x800b0109

The 'Some Update Files Aren't Properly Signed' error (Error code: 0x800b0109) can occur due to several reasons, including:

  • Corrupted update files: Windows update files can sometimes become corrupted during the download or installation process. This corruption can cause the digital signatures to become invalid.
  • Interference from third-party software: Antivirus programs or firewall software may block or interfere with the update process, preventing the correct verification of digital signatures.
  • Issues with the Windows update service: Problems with the Windows Update service itself can lead to errors in the update process, including issues with verifying digital signatures.
  • Date and Time settings: Incorrect date and time settings on your computer can cause issues with the Windows update process. It's essential to have the correct date and time set on your system.
  • Corrupted Windows update components: Over time, the components of the Windows Update service may become corrupted or misconfigured, leading to errors during the update process.

Fix Windows 11 Update Error 0x800b0109

Fixing the 0x800B0109 error helps you install the latest Windows updates, which keep your computer safe from potential problems, and ensures your computer stays up to date with new features and improvements.

1. Run the Windows Update troubleshooter

Most of the minor issues with Windows Update can be fixed by simply running the Windows Update troubleshooter. So, the first step you should take when trying to fix Windows Update errors is running the built-in troubleshooter, which you can access from Windows Settings.

Press the Windows key and select 'Settings'.

Under the 'System' section, click on 'Troubleshoot' on the right pane.

On the Troubleshoot settings page, click on 'Other troubleshooters'

Next, click on the 'Run' button next to 'Windows Update'.

Wait for the troubleshooter to identify and resolve the problem. After completing the troubleshooting process, restart your computer, and then try to update Windows to see if it resolves the update error 0x800b0109.

2. Check Date and Time Settings

The incorrect date and time settings can cause update issues. If your computer's clock is set to the wrong date or time, it can affect the synchronization of various processes, including updates. So, make sure your computer's clock shows the correct date and time to avoid update problems.

Right-click on the clock in the bottom-right corner of your screen (system tray) and select 'Adjust data and time'.

In the Date & Time settings, choose your 'Time zone' from the drop-down list.

Next, make sure the 'Set time automatically' toggle is turned On.

After changing the time settings, reboot your computer and check if the Windows update works now.

3. Disable Third-Party Antivirus/Firewall

Sometimes, security software can interfere with the update process. Firewalls can also block the network connections needed to download updates from Microsoft's servers. To fix this issue, you can temporarily disable your third-party antivirus or firewall while you're performing the update process.

Open your antivirus software and look for an option to temporarily disable it. It might be labeled as 'Disable Protection', 'Real-time protection', or something similar. Remember to re-enable it after the update is complete to keep your computer protected.

Most security programs also let you turn off their antivirus protection from their context menus in the Windows 11 system tray. To do this, right-click on the security program's icon in the bottom-right corner of your Windows 11 screen (near the clock), and find the option to 'temporarily disable' or 'pause' the antivirus.

4. Check the Windows Update and BITS Services

Windows Updates and Background Intelligent Transfer Service (BITS) are Windows services that are essential for Windows updates. Make sure these services are running in your system.

Open the Run command box, type services.msc, and hit Enter.

In the Services app, click the ‘Name’ column at the top to sort the services alphabetically. 

From the list, double-click the 'Windows Update' service to change its properties.

In the properties window, set the 'Startup type' setting to 'Automatic'.

Click the 'Start' button to start the Windows update service. Then, click 'Apply' and then 'OK' to save the settings.

After that, locate and double-click the 'Background Intelligence Transfer Service'.

Then, set the Startup type of the service to 'Manual' and click 'Apply'.

Then, close the Service app and restart your computer.

5. Run DISM and SFC Scans

You might encounter a Windows update error due to missing or damaged system files on your computer. To fix this issue, you can use System File Checker (SFC) and Deployment Image Servicing and Management (DISM) tools to scan your computer for corrupt files.

System File Checker, known as SFC, is a built-in Windows command-line tool. It scans important Windows files and replaces any that are incorrect, corrupted, or damaged.

To start with, type cmd in the Windows search, and select 'Run as administrator' to open Command Prompt with administrative privileges.

In the Command Prompt window, type the following command and press Enter:

sfc /scannow

If the above command fails, try this instead:

sfc /scannow /offbootdir=c:\ /offwindir=c:\windows 

This scan may take some time. SFC will check for corrupt files and automatically replace them. Once the scan is complete, restart your computer to see if the error is resolved.

If SFC doesn't find any errors or if you want to perform a more advanced check, you can use DISM. The DISM tool lets administrators and experts scan and fix Windows images, including Windows Recovery Environment, Setup, and WinPE.

Open Command Prompt as an administrator. In the Command Prompt, run the following command to check for corruption in the local Windows image:

Dism /Online /Cleanup-Image /CheckHealth

If no corruption is detected, you can perform a more thorough scan with:

Dism /Online /Cleanup-Image /ScanHealth

This process may take a few minutes.

Finally, use the RestoreHealth option to download and replace the Windows image using Windows Update:

Dism /Online /Cleanup-Image /RestoreHealth

This step can take 15 minutes or more, depending on the extent of corruption.

Restart your computer to apply the changes and check if you've resolved the 'Some Update Files aren’t signed correctly' issue when updating Windows 11. If the problem persists, proceed to the next method.

6. Reset Windows Update Components and Policies

Resetting Windows Update not only resolves the Update Error 0x800b0109 issue but also addresses the most prevalent problems associated with the Windows Update service.

To fully reset the Windows Update Agent, you should perform several steps, including re-registering BITS files and associated DLL files, clearing the Software Distribution and Catroot2 folders, and resetting all Windows update services.

Below, you'll find a step-by-step guide on how to restore the Windows Update service and its components to their default settings. Just follow the commands one after another to reset Windows Update components.

Open Command Prompt with administrative privileges. First, you should stop three services: BITS (Background Intelligent Transfer Service), the Windows Update service, and the Cryptographic service. To do this, type and execute the following commands one by one, pressing ENTER after each:

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

Following that, remove all files named qmgr*.dat created by BITS from your device using the following commands:

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

Afterward, press Y and then Enter to confirm this action.

After that, change the names of the SoftwareDistribution and catroot2 directories on your system. These folders hold updates that have already been downloaded and might be corrupted (they can also serve as backups in case of any issues). When we restart the Windows update service, these folders will be recreated to store files. To rename the folders, use the following commands:

Rename %Systemroot%\SoftwareDistribution\DataStore to DataStore.bak
Rename %Systemroot%\SoftwareDistribution\Download to Download.bak
Ren %systemroot%\system32\catroot2 catroot2.bak

Next, use the following commands to reset the security descriptors of the BITS and Windows Update services to their default settings:


Once you've completed that, enter the following command to navigate to the System32 folder (if you aren't already there):

cd /d %windir%\system32

Following that, you should re-register all the dynamic libraries (DLLs) associated with BITS and Windows Update services. Execute these commands one by one, pressing Enter after each. When a prompt appears after each command, simply click 'OK' to continue.

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

Once you've re-registered all the DLL files, it's time to reset the network configurations (Winsock) that might contain incorrect or corrupted logs. Execute the following commands:

netsh winsock reset
netsh winsock reset proxy

Finally, restart the services we stopped earlier. Enter these commands one by one and press Enter:

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

After completing all the steps mentioned above, restart your computer. This should resolve the Windows Update error code: 0x800b0109.

7. Remove the Windows Update Registry Entry

Deleting the Windows Update registry entry is a potential solution that some users have found effective in resolving error 0x800b0109. However, we strongly recommend you create a backup of the registry or create a system restore point before deleting any registry entries.

Once you've taken the backup, follow these steps to delete the Windows Update registry entry:

Launch the Run dialog by pressing the Windows +R. Then, type regedit and click 'OK' in the Run dialog to open the Registry Editor.

Navigate to the below location or clear the registry address bar and enter the following key path:


Once you're in the above location, right-click the 'WindowsUpdate' registry entry, and choose the 'Delete' option from the context menu.

Confirm the deletion by clicking 'Yes' when prompted.

8. Turn Off Proxy Settings

Disabling proxy settings is important because they can interfere with the Windows update process and sometimes cause errors. When you turn off the proxy server temporarily, you can see if they're causing the problem. Here's how to do it:

Press the Windows+I to open the Settings application.

Navigate to 'Network & Internet' and access the 'Proxy' section on the right-hand side.

Within the Proxy settings window, click on the 'Edit' button next to the 'Use a proxy server' option.

In the Edit proxy server window, switch off the 'Use a proxy server' toggle. Then, click 'Save' and then close the Settings window.

Now, try to update your Windows system once more to determine if the error has been resolved.

9. Perform a Clean Boot

Performing a clean boot is important because it helps identify and resolve conflicts that can occur between startup services and the Windows update process. It essentially sets up a fresh and clean environment specifically for Windows Update to work smoothly. Here are the steps to follow:

Press the Windows key+R to open the Run dialog. Type msconfig and press Enter to open the System Configuration window.

In the General tab, choose 'Selective startup' and uncheck the box that says 'Load startup items'.

Proceed to the 'Services' tab and check the box that reads 'Hide all Microsoft services'.

Click 'Disable all' to disable all non-Microsoft services.

Move on to the 'Startup' tab and click 'Open Task Manager'.

Inside the Task Manager, disable each startup application by right-clicking on them and selecting 'Disable'.

Close the Task Manager, and click 'Apply', followed by 'OK' in the System Configuration window.

Once it's done, restart your computer. Try to update your Windows system once again to check if the error has been resolved.

To return your system to its normal startup configuration, reopen the System Configuration tool. Under the 'General' tab, select 'Normal startup' and click 'Apply', then 'OK'.

Then, restart your computer.

10. Manually Download Update from Microsoft Update Catalog

If the 0x800b0109 error is not fixed yet, you have the option to manually download the problematic update from the Microsoft Update Catalog and install it.

Launch any web browser and go to the Microsoft Update Catalog website.

On the Microsoft Update Catalog homepage, type the 'KB' number of the specific update you wish to download in the search box. If you're not sure about the KB number, you can use more general terms like 'Windows 11'. Then, click 'Search'.

Find the update you want to download from the results, and click the 'Download button next to it.

This action will launch a new window displaying the download link for the update. Click the link, and when prompted, choose your preferred location to save the file, as you normally would.

After downloading the file, you can simply double-click it to install it on your computer. Once the update is installed, you may need to restart your computer for the changes to take effect.

11. Perform an In-Place Windows Upgrade

When all else fails to fix the error 0x800b0109, you can try an in-place Windows upgrade as a last resort. This means reinstalling Windows on your computer using the latest ISO file. This fresh installation of Windows can often fix the 0x800b0109 error, along with any other issues that previous solutions couldn't solve.

First, create a Windows 11 Installation Media or download the latest Windows 11 ISO file.

Once the bootable media is ready, insert the bootable USB flash drive or DVD into the PC and run the ‘setup.exe’ file. If you have a Windows 11 ISO file, mount the file and run the setup.

Confirm 'Yes' when the UAC prompt appears, and click 'Accept' to accept the terms.

Choose 'Upgrade this PC now' and click 'Next'.

Windows will begin downloading the necessary files. Once again, agree to the terms and click 'Next'.

In this step, you can choose what to save on your computer from your current Windows setup. You have three options: 'Keep personal files and apps', Keep personal files only, or Nothing (delete everything). If you want to keep your files and apps, choose the first option and click 'Next'.

Finally, click 'Install' to start the upgrade process.

We hope that at least one of the 11 solutions provided in this guide will likely resolve the update error 0x800b0109 on your computer.