Troubleshoot Windows Update error 0x80240439

Updated 2026-04-29 · CC-BY-4.0 (MicrosoftDocs/SupportArticles-docs, repo license verified 2026-10-09) · retrieved 2026-10-09 · original

Troubleshoot Windows Update error 0x80240439

Summary

Windows Update error 0x80240439 (WU_E_NOT_INITIALIZED) occurs if the Windows Update agent starts but can't complete its startup sequence. This article describes the symptoms of this error, and provides step-by-step instructions to help you resolve it.

Symptoms

You install a Windows update, but the installation fails, and you see error code 0x80240439 reported.

To get more information, follow these steps:

1. Check the %windir%\Logs\WindowsUpdate\WindowsUpdate.log file for entries that resemble the following example:

   Agent -- WARNING: WU client failed Searching for update with error 0x80240439
   Agent -- WARNING: Exit code = 0x80240439
   

2. To check the state of the Windows Update service, open a Windows PowerShell command prompt, and then run the following cmdlets:

   Get-Service wuauserv | Select-Object Name, Status, StartType
   Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate" -ErrorAction SilentlyContinue
   

Cause

This error occurs if the Windows Update service starts but can't finish its startup sequence. Any of the following conditions can cause this issue:

• The Windows Update agent data store is corrupted.
• The Windows Update registry configuration is damaged or incomplete.
• The state files in the %windir%\SoftwareDistribution folder are corrupted.
• A system policy or Group Policy setting blocks the agent from starting.
• A recent Windows Update reset didn't finish the reinitialization process.

Resolution

Important

Before you troubleshoot this issue, back up the operating system disk. For information about this process for virtual machines (VMs), see About Azure Virtual Machine restore.

Step 1: Reset the Windows Update agent

To reset the Windows Update agent, follow these steps:

1. Open an administrative Command Prompt window, and run the following commands:

   net stop wuauserv
   net stop bits
   net stop cryptSvc
   
   ren %windir%\SoftwareDistribution SoftwareDistribution.old
   ren %windir%\System32\catroot2 catroot2.old
   
   net start cryptSvc
   net start bits
   net start wuauserv
   

   Note

   • If you have to run these commands more than one time, delete the existing SoftwareDistribution.old and catroot2.old folders before each subsequent run.
   • This sequence of commands stops the Windows Update service, clears the data store, and then restarts the service.

2. After the commands finish running, try again to install the update. If the update still doesn't install, go to step 2.

Step 2: Reregister Windows Update components

To reregister the DLLs that the Windows Update agent needs, run the following commands at the command prompt:

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

Note

On computers that run Windows versions that are older than Windows 10, you might also have to reregister the following DLLs:

regsvr32 /s wuaueng.dll
regsvr32 /s wucltui.dll
regsvr32 /s wuweb.dll
regsvr32 /s gpkcsp.dll
regsvr32 /s sccbase.dll
regsvr32 /s slbcsp.dll

After the commands finish running, restart the computer. Then, try again to install the update. If the update still doesn't install, go to step 3.

Step 3: Verify Group Policy settings

To generate a Group Policy report, run the following command at the command prompt:

gpresult /h gpresult.html

In the report, review Computer Configuration > Administrative Templates > Windows Components > Windows Update for policies that might block initialization. If you find such policies, reconfigure or disable them.

If you make changes, run the following command:

gpupdate /force

Restart the computer, and try again to install the update. If the update still doesn't install, take one of the following actions:

• If the affected computer is a VM, go to step 4.
• Otherwise, go to step 5.

Step 4: Use the Run command reset tool (Azure)

If the previous steps don't resolve the issue on an Azure VM, try the Azure VM Windows Update Reset Tool. You can run the tool directly from the VM's Azure portal page by using Operations > Run command. When you use this method, you don't have to sign in to the VM.

This tool resets the Windows Update servicing stack. The reset can clear memory-related lock states in the update agent.

After you run the tool, try again to install the update. If it still doesn't install, go to step 5.

Step 5: Check update service configuration

If you use Windows Server Update Services (WSUS) or a similar service to manage updates, follow these steps:

1. Verify that the VM can connect to the WSUS server URL.
2. Make sure that firewalls and NSG rules (for VMs) allow outbound connections to the WSUS server or Windows Update endpoints.
3. If you use Azure Update Manager, verify that the Azure Monitor Agent (AMA) or the Log Analytics agent (MMA) is healthy. The particular agent to check depends on your configuration.
4. Try again to install the update. If the update still doesn't install, contact Microsoft Support for assistance.