How to Fix Windows 11 Update Error 0x800f0983 (KB5066835)

Windows 11 users have recently faced update failures with error 0x800f0983, particularly when installing KB5066835. This guide explains what causes it and how to fix it safely using verified methods.

What Causes Error 0x800f0983?

This update error appears when the Windows Update process encounters damaged or incomplete files. Typical causes include:

Corrupted SoftwareDistribution or Catroot2 cache folders
Broken component store (WinSxS) or registry entries
Outdated regional or language pack mismatch
Interrupted update download or power loss during installation

Fix 1 – Reset Windows Update Components

If cached files are blocking the update, reset all update services.

Open Command Prompt (Admin)
Run each command in order:

net stop wuauserv
net stop bits
net stop cryptsvc
del /s /q %windir%\SoftwareDistribution\*
del /s /q %windir%\System32\catroot2\*
net start wuauserv
net start bits
net start cryptsvc

Restart your PC and check Settings → Windows Update → Check for updates.

Fix 2 – Uninstall KB5066835 and Reinstall Manually

If the update installed partially, remove it first.

wusa /uninstall /kb:5066835

Then go to the Microsoft Update Catalog, search KB5066835, download the matching .msu file for your system, and install it manually.

Fix 3 – Use Windows Update Troubleshooter

Open Settings → System → Troubleshoot → Other troubleshooters
Click Run beside Windows Update
Apply suggested fixes and restart your device

Fix 4 – Clear Pending Update and Temp Files

Press Win + R, paste: C:\Windows\SoftwareDistribution\Download Delete everything inside.
Go to: C:\Windows\WinSxS\Temp Delete Pending.xml if present.
Restart and try updating again.

Fix 5 – Repair System Files with DISM and SFC

Run both tools in the correct order:

DISM /Online /Cleanup-Image /RestoreHealth
sfc /scannow

When both scans finish, reboot before checking for updates.

Fix 6 – Re-install or Switch Language Pack

If your PC uses a non-English language pack, it can cause update mismatch.

Go to Settings → Time & Language → Language & Region
Change display language to English (United States)
Restart and run the update
Switch back to your preferred language later

Fix 7 – Perform an In-Place Upgrade (Last Resort)

When all else fails, refresh system files without losing data.

Download the Windows 11 Installation Assistant
Launch it and choose Upgrade this PC now
Complete setup → this reinstalls system components and fixes persistent errors like 0x800f0983

The Windows 11 update error 0x800f0983 (KB5066835) is usually caused by damaged update files, system corruption, or language pack conflicts. By methodically following the above steps—resetting update components, clearing cache folders, running DISM and SFC repairs, and performing an in-place upgrade if needed—you can restore Windows Update to full functionality.

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If the issue persists even after these fixes, it’s best to manually install the update from Microsoft Update Catalog or use the Windows 11 Installation Assistant for a clean repair without losing your files.

How to Fix Windows 11 Update Error 0x800f0983 (KB5066835 Installation Failed)