Fix Windows Update Error 0x80070306

Issue type: Windows Update install processing failure | Applies to: Windows 10, Windows 11

Windows update error 0x80070306 means Windows Update hit one or more errors while processing the request. It is not specific enough to blame one service immediately, so the right fix is to isolate the update pipeline: run the troubleshooter, reset Windows Update components, repair Windows with DISM and SFC, install the failed KB manually, and check logs if the same code returns.

This code often appears as Install error – 0x80070306 on cumulative updates. Because it is a broad processing failure, guessing from the code alone can waste time. Treat it as a failed update transaction and work through the update system from the safest fixes to the deeper repairs.

Before you begin, copy the exact KB number from Settings → Windows Update → Update history. If one update is failing, the manual KB install path may work. If every update fails, the local update engine needs repair.

What to Do First: Fix Windows Update Error 0x80070306

1. Restart the PC once and check whether windows update error 0x80070306 appears again.
2. Copy the failed KB number from Windows Update → Update history.
3. Run the Windows Update troubleshooter before using command-line resets.
4. Disconnect VPN and temporarily pause third-party antivirus during the test.
5. Reset SoftwareDistribution and catroot2 if the same KB fails again.
6. Run DISM and SFC, then retry Windows Update or install the KB manually.

Fix 2: Run the Windows Update Troubleshooter

Start with the built-in troubleshooter because it can repair common update states and service problems without removing files manually.

1. Open Settings.
2. Go to System → Troubleshoot → Other troubleshooters.
3. Click Run next to Windows Update.
4. Apply any fixes it suggests.
5. Restart and check for updates again.

If Windows Update changes from an install error to a pending state, use Windows Update pending install before continuing.

Fix 3: Pause Updates, Restart, and Resume Updates

A stuck update session can sometimes be cleared without a full reset. This is a quick fix when the error appeared after several retries in the same session.

1. Open Settings → Windows Update.
2. Click Pause updates for one week.
3. Restart the PC.
4. Return to Windows Update and click Resume updates.
5. Let Windows scan again from a fresh session.

Fix 4: Reset Windows Update Components

If the update keeps failing, rebuild the main Windows Update folders. This clears stale downloads, bad metadata, signature cache problems, and stuck install state.

net stop wuauserv
net stop bits
net stop cryptSvc
net stop msiserver
ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
ren C:\Windows\System32\catroot2 catroot2.old
net start msiserver
net start cryptSvc
net start bits
net start wuauserv

Restart the PC after the reset. Then run Windows Update before opening other utilities.

If Windows Update stays at 0% after the reset, check Windows Update stuck at 0 percent.

Fix 5: Repair the Component Store with DISM

If the update install fails after the component reset, repair Windows servicing files. Cumulative updates depend heavily on the component store.

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

Wait for DISM to complete. It can pause for several minutes. If DISM reports success, continue with SFC.

Fix 6: Run SFC After DISM

SFC repairs protected system files after DISM repairs the source Windows uses for those repairs.

sfc /scannow

Restart after SFC completes. Then retry the failed KB.

Fix 7: Disable VPN, Proxy, and Security Interference

Security tools and network filters can interfere with update download, verification, or install. Test without them temporarily.

1. Disconnect VPN software.
2. Turn off any manual proxy you do not need.
3. Temporarily pause third-party antivirus.
4. Run Windows Update immediately.
5. Turn protection back on after testing.

If the update works, create allow-list rules in the security tool instead of leaving protection off.

Fix 8: Install the Failed Update Manually

If one KB is failing but other updates install, download the failed package manually. This bypasses part of Windows Update’s automatic delivery chain.

1. Copy the KB number from Update history.
2. Search for it in Microsoft Update Catalog.
3. Download the correct package for your Windows version and architecture.
4. Run it as Administrator.
5. Restart the PC.

If the standalone installer fails, use DISM Add-Package:

DISM /Online /Add-Package /PackagePath:"C:\Users\YourName\Downloads\update.msu"

Fix 9: Check CBS and Windows Update Logs

If 0x80070306 returns after every fix, read the logs. The log may show the actual underlying error that happened before Windows showed the broad processing code.

C:\Windows\Logs\CBS\CBS.log
Get-WindowsUpdateLog

Search for 0x80070306, the failed KB number, failed, package, access denied, and corrupt.

Fix 10: Use Fix Problems Using Windows Update or In-Place Repair

If every update fails and normal repairs do not work, use Windows’ built-in repair option if available. It reinstalls the current Windows version using Windows Update while keeping files, apps, and settings.

1. Open Settings → System → Recovery.
2. Look for Fix problems using Windows Update.
3. Select Reinstall now if available.
4. Let the repair complete and restart.

If that option is missing, use a standard in-place repair upgrade with Microsoft installation media.

Common Mistake

The common mistake is assuming 0x80070306 has one exact cause. It is a broad processing error, so a single random command may not fix it. Work through the update pipeline in order: troubleshooter, reset components, DISM, SFC, manual KB install, then logs.

Best Next Step

If the error keeps returning, use Microsoft’s Windows Update troubleshooter first, then inspect logs for the real underlying failure. Microsoft’s general update repair path starts here: Troubleshoot problems updating Windows — Microsoft Support.

Frequently Asked Questions

What does Windows Update error 0x80070306 mean?

It means one or more errors occurred while Windows Update was processing the update request. The code is broad, so logs and update state matter more than guessing from the number alone.

Is 0x80070306 a service error?

Not always. It can appear during update installation, service processing, package verification, or component repair. Check services, but do not treat it only as a service-control issue.

Can resetting Windows Update fix 0x80070306?

Yes, if the failure comes from bad cache, broken metadata, catroot2 verification issues, or a stuck update queue. It is one of the most important fixes for this code.

Should I manually install the KB?

Yes, if only one update fails and you know the KB number. Manual installation can bypass a broken automatic delivery path.

Does 0x80070306 require reinstalling Windows?

Usually no. Try the troubleshooter, update reset, DISM, SFC, security software test, and manual KB install first. Use repair reinstall only if every update keeps failing.