How to fix
KB5012643 fails to install
on Windows

Hello. I tried to install the KB5012643 update on my Windows 11 computer but it failed. Is there anything I can do to be able to download this update?

Microsoft regularly releases updates for the Windows operating system, which contain bug fixes, new features, and security patches. It is important to keep Windows up-to-date to avoid stability issues and protect against vulnerabilities that can be exploited by cybercriminals.

The latest update for Windows 11 is KB5012643, which addresses various problems such as video subtitles being partially cut off, memory leaks, and issues with Windows going into BitLocker recovery after a servicing update. However, some users have reported difficulty in installing this update.

It is not clear why KB5012643 is failing to install in Windows 11, but common reasons for update failures include interference from third-party security software, corrupted files, and malfunctioning Windows services or update components. In this guide, we will provide 7 steps to help fix the issue of KB5012643 not installing in Windows 11.

Keep in mind that manual troubleshooting can be time-consuming. You can use an automatic maintenance tool like [d1] to help fix most system errors, BSODs,[ref en-1] corrupted files, registry[ref en-2] issues, or clear cookies and cache.[ref en-3] Otherwise, follow the step-by-step instructions provided in the guide.

Solution 1. Repair Corrupted System Files

Use Command Prompt commands to repair system file corruption:

• Open Command Prompt as administrator
• Use the following command and press Enter:
  sfc /scannow

• Reboot your system
• If SFC returned an error, then use the following command lines, pressing Enter after each:
  DISM /Online /Cleanup-Image /CheckHealth
  DISM /Online /Cleanup-Image /ScanHealth
  DISM /Online /Cleanup-Image /RestoreHealth

Solution 2. Disable Third-Party Security Software

Sometimes antivirus software can block legitimate processes mistakenly. You should try disabling your antivirus and trying to run the update again.

Solution 3. Run Windows Update Troubleshooter

• Click the Windows button and select Settings
• Select System from the left pane, then scroll down on the right pane, and click on Troubleshoot
• Click on Other troubleshooters

• Locate the Windows Update troubleshooter and hit the Run button

Solution 4. Restart Windows Services

• Type services in the search bar and launch the Services utility
• Find Windows Update in the list
• Double-click on it, set the Startup type to Automatic, and click Apply
• Now click on Restart the Service

• Do the same with Background Intelligent Transfer Service

Solution 5. Reset Windows Update Components

• Open the Command Prompt as an Administrator
• Type the following commands one by one and press Enter after each:

net stop bits

net stop wuauserv

net stop cryptsvc

Del "%ALLUSERSPROFILE%\Application Data\Microsoft\Network\Downloader\qmgr*.dat"

Ren %Systemroot%\SoftwareDistribution\DataStore DataStore.bak

Ren %Systemroot%\SoftwareDistribution\Download Download.bak

Ren %Systemroot%\System32\catroot2 catroot2.bak

sc.exe sdset bits D:(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)(A;;CCLCSWLOCRRC;;;AU)(A;;CCLCSWRPWPDTLOCRRC;;;PU)

sc.exe sdset wuauserv D:(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)(A;;CCLCSWLOCRRC;;;AU)(A;;CCLCSWRPWPDTLOCRRC;;;PU)

cd /d %windir%\system32

regsvr32.exe atl.dll

regsvr32.exe urlmon.dll

regsvr32.exe mshtml.dll

regsvr32.exe shdocvw.dll

regsvr32.exe browseui.dll

regsvr32.exe jscript.dll

regsvr32.exe vbscript.dll

regsvr32.exe scrrun.dll

regsvr32.exe msxml.dll

regsvr32.exe msxml3.dll

regsvr32.exe msxml6.dll

regsvr32.exe actxprxy.dll

regsvr32.exe softpub.dll

regsvr32.exe wintrust.dll

regsvr32.exe dssenh.dll

regsvr32.exe rsaenh.dll

regsvr32.exe gpkcsp.dll

regsvr32.exe sccbase.dll

regsvr32.exe slbcsp.dll

regsvr32.exe cryptdlg.dll

regsvr32.exe oleaut32.dll

regsvr32.exe ole32.dll

regsvr32.exe shell32.dll

regsvr32.exe initpki.dll

regsvr32.exe wuapi.dll

regsvr32.exe wuaueng.dll

regsvr32.exe wuaueng1.dll

regsvr32.exe wucltui.dll

regsvr32.exe wups.dll

regsvr32.exe wups2.dll

regsvr32.exe wuweb.dll

regsvr32.exe qmgr.dll

regsvr32.exe qmgrprxy.dll

regsvr32.exe wucltux.dll

regsvr32.exe muweb.dll

regsvr32.exe wuwebv.dll

netsh winsock reset

net start bits

net start wuauserv

net start cryptsvc

• Wait for the process to finish and restart your PC

Solution 6. Install the Update Manually

If automatic download would not succeed, we recommend trying to download and install the update manually.

• Go to the official Microsoft Update Catalog website
• Type the KB number KB5012643 into the search bar, and press Enter or click Search

• You will find many different versions on the update – you need to find the one that matches your PC specs and Windows version (as a home user, ignore Windows server versions)
• After picking the correct version, click the Download button and proceed with the on-screen instructions
• Restart your system once done.

Solution 7. Repair Install Windows

• Visit the official Microsoft website to download Windows 11 Installation Media
• Run the Media Creation Tool and select Create Installation Media for another PC
• Select your USB drive
• Let the Process complete of writing the Installation files to the USB drive
• Click Finish
• On the PC you wish to upgrade, Press Windows + E to open the File Explorer
• Open the Removable drive and click Setup.exe

• Accept the license terms on the next screen
• Confirm the Upgrade options – Files, apps and Settings are kept
• Click Install, and the upgrade should start