Fix Windows Update Error 0x80070020 – Windows 10, Windows 11 2026

This method eliminates software conflicts by starting Windows with minimal services.

1. Press Windows + R, type msconfig, and press Enter
2. In System Configuration, click the Services tab
3. Check Hide all Microsoft services
4. Click Disable all to disable third-party services
5. Go to the Startup tab and click Open Task Manager
6. In Task Manager, disable all startup programs by right-clicking each and selecting Disable
7. Close Task Manager and click OK in System Configuration
8. Restart your computer when prompted
9. After restart, immediately open Settings → Windows Update
10. Click Check for updates and allow the installation to complete

Verification: Run winver from Run dialog to confirm the new build number matches the installed update.

This method rebuilds corrupted Windows Update components that may be causing file access issues.

1. Press Windows + X and select Windows PowerShell (Admin)
2. Stop Windows Update services by running these commands:

Stop-Service -Name wuauserv -Force
Stop-Service -Name cryptSvc -Force
Stop-Service -Name bits -Force
Stop-Service -Name msiserver -Force

3. Clear the Windows Update cache:

Remove-Item -Path "C:\Windows\SoftwareDistribution\*" -Recurse -Force
Remove-Item -Path "C:\Windows\System32\catroot2\*" -Recurse -Force

4. Re-register Windows Update DLLs:

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 gpkcsp.dll
regsvr32 /s sccbase.dll
regsvr32 /s slbcsp.dll
regsvr32 /s cryptdlg.dll

5. Restart the Windows Update services:

Start-Service -Name wuauserv
Start-Service -Name cryptSvc
Start-Service -Name bits
Start-Service -Name msiserver

6. Restart your computer and attempt the update again

Verification: Check Windows Update service status with Get-Service wuauserv - it should show "Running".

Corrupted system files can cause access conflicts during updates. This method repairs the Windows image and system files.

1. Open Command Prompt as Administrator
2. Run DISM to repair the Windows image:

DISM /Online /Cleanup-Image /CheckHealth
DISM /Online /Cleanup-Image /ScanHealth
DISM /Online /Cleanup-Image /RestoreHealth

3. After DISM completes, run System File Checker:

sfc /scannow

4. Wait for both scans to complete (this may take 30-60 minutes)
5. Restart your computer
6. Attempt the Windows Update installation again

Verification: Check the CBS.log file at C:\Windows\Logs\CBS\CBS.log for "Windows Resource Protection found corrupt files and successfully repaired them" message.

Security software often locks system files during real-time scanning, causing update conflicts.

1. Temporarily disable Windows Defender Real-time Protection:
2. Open Settings → Privacy & Security → Windows Security
3. Click Virus & threat protection
4. Under Virus & threat protection settings, click Manage settings
5. Turn off Real-time protection temporarily
6. If using third-party antivirus, disable it through its system tray icon or settings
7. Disable Windows Defender through Group Policy (for advanced users):

gpedit.msc

8. Navigate to Computer Configuration → Administrative Templates → Windows Components → Microsoft Defender Antivirus
9. Double-click Turn off Microsoft Defender Antivirus
10. Select Enabled and click OK
11. Run gpupdate /force to apply the policy
12. Restart your computer and attempt the update
13. After successful update, re-enable all security software

Verification: Check Windows Security status in Settings to confirm protection is disabled, then verify update installation succeeds.

When automatic updates fail, manually downloading and installing updates bypasses many file access issues.

1. Identify the specific update causing the error:
2. Open Settings → Windows Update → Update history
3. Note the KB number of the failed update
4. Visit the Microsoft Update Catalog website
5. Search for the KB number (e.g., KB5035857)
6. Download the appropriate update for your system architecture (x64 for 64-bit systems)
7. Before installation, stop Windows Update service:

Stop-Service -Name wuauserv -Force

8. Navigate to the downloaded .msu file location
9. Right-click the file and select Run as administrator
10. Follow the installation wizard prompts
11. If installation fails, extract and install manually:

expand -F:* "C:\path\to\update.msu" "C:\temp\update"
DISM /Online /Add-Package /PackagePath:"C:\temp\update\update.cab"

13. Restart your computer after installation
14. Restart Windows Update service:

Start-Service -Name wuauserv

Verification: Check Settings → Windows Update → Update history to confirm the update appears as "Successfully installed".