How to fix KB5012599 failed to install on Windows?

Microsoft has recently released a Windows 10 with various security fixes. The error code appears when users try to install the KB5012599 Windows 10 update. The update improves the quality of the servicing stack.

Update package downloads successfully but the installation process fails which gives this error. Sometimes when users try to update it pushes back to the desktop, boots to a black screen, or appears to be installed successfully but re-offers to the same system. This can happen due to a number of reasons, like system file corruption, outdated drivers, security software or VPN, malfunction of update components, or the SoftwareDistribution folder.

We recommend you check your internet connection, as you need a stable connection to download and install windows updates. Usually, the updating process can be restored by running a built-in update troubleshooter or resetting the update components. If this doesn’t fix the error, follow the step-by-step guide provided below carefully.

Before getting into advanced troubleshooting, try these basic solutions:

1. Disconnect nonessential devices such as USB flash drives or external HDD, headphones, or printers.
2. Disable any third-party antivirus that might interfere with the windows update. Turn it back on after updates are successfully installed.
3. Disconnect your VPN (if it’s on) then look for windows updates.

Perform a Clean boot State

Sometimes third-party software cause conflicts for windows updates, clean booting of your system can help you get rid of such issues. Follow these steps to perform a clean boot on your computer:

1. Go to the search box on your computer.
2. Type msconfig and press enter.
3. Then select System configuration and go to the Services tab
4. Select Hide all Microsoft services and open Disable all option.
5. Then Go to the Startup tab > Open Task Manager > Disable all the unnecessary services running there. 
6. Restart your system and check if the update gets uninstalled perfectly.

Run the Update Troubleshooter

Running the update troubleshooter can help you check the status of windows update and its related services, repair, and resets windows update components. It also clears out the windows update-related temporary files, and checks for pending updates. Here’s how you can run the update troubleshooter on your system:

• Press the Windows + I keys to open the Settings app.
• Go to Update and Security and click on Troubleshooter.
• Select Additional troubleshooters
• Locate windows update and then click on Run the Update troubleshooter
• Once the troubleshooting is complete, restart your system.

Doing this will help you fix any problems that are preventing the windows update from installing and downloading.

Run DISM command

Sometimes corrupted system files can restrict your windows download. We suggest you to repair corrupted files that will fix KB5012599 failed to install on Windows issue. Follow the below steps to use Command Prompt commands to repair system file corruption:

• Open Command Prompt as administrator and then type the following command. Then press Enter:
• sfc /scannow
• Restart your system and if any SFC error returns, then use the following command lines, press Enter after each:
• DISM /Online /Cleanup-Image /CheckHealth
  DISM /Online /Cleanup-Image /ScanHealth
  DISM /Online /Cleanup-Image /RestoreHealth

Reset Windows Update Components

If you still get the error after running the troubleshooter and the windows update fails to download, then reset windows update components by following the below steps:

• Open Command Prompt as administrator.
• Copy and paste the following commands, press Enter after each:
• net stop bits
• net stop wuauserv
• net stop appidsvc
• net stop cryptsvc
• Del “%ALLUSERSPROFILE%\\Application Data\\Microsoft\\Network\\Downloader\\*.*”
• rmdir %systemroot%\\SoftwareDistribution /S /Q
• rmdir %systemroot%\\system32\\catroot2 /S /Q
• regsvr32.exe /s atl.dll
• regsvr32.exe /s urlmon.dll
• regsvr32.exe /s mshtml.dll
• netsh winsock reset
• netsh winsock reset proxy
• net start bits
• net start wuauserv
• net start appidsvc
• net start cryptsvc
• These commands will first stop the windows update service and its related services, then rename the SoftwareDistribution folder to SoftwareDistribution.old After that restart the windows update and its related services.

Note: Where windows store update files, If any files in this folder get corrupted this may cause windows updates fails to install.

Clear Windows Update Files

If you’re not comfortable with resetting windows update components, you can clear windows to update files. Follow the below steps to do so:

• Type services.msc on the start menu search and hit Enter.
• It will open the Windows services console, scroll down and navigate the Windows update service.
• Right-click on windows update service, and select stop. Do the same with BITS (Background  Intelligent Transfer Service).
• Press Windows + E keys and go to the following location.

C:\Windows\SoftwareDistribution\Download

• Delete everything in the download folder but don’t delete the folder itself. Press CTRL + A to select everything and then press delete on your keyboard. Doing this will remove the files.
• Open Windows services again and restart both services ( Windows update, BITS) that you stopped earlier.
• Or rename the Software Distribution folder ( C:\Windows\).
• After that restart the services you previously stopped and check for windows updates again.

Delete the SoftwareDistribution Folder

If clearing Windows update files doesn’t work for you, try deleting the SoftwareDistribution folder, here’s how you can do that:

• Search the taskbar for the following address:
•  C:\\Windows\\SoftwareDistribution
• Select all the files inside the folder and deleted them. Make sure to delete the folder.

Switch to Google DNS

If your Windows update isn’t downloading or you’re stuck while downloading then change your DNS address by following the steps below to do so:

1. Press Windows + R keys simultaneously on your keyboard.
2. In the run dialog box, type control, and press Enter.
3. Click on Network and Internet and choose Network and Sharing Centre option.
4. Choose Change Adapter Settings from the left side menu.
5. Right-click on the connection you are currently using and select Properties.
6. Scroll down and click on Internet protocol version 4 (TCP/IPv4) and then click on the Properties button.
7. Select Use the following DNS Server addresses.
8. Type 1.1.1.1 into the Preferred DNS server, then 1.0.0.1 into the Alternative DNS server. This will change your DNS to a popular 1.1.1.1 server.
9. Click Ok to apply your changes.
10. Try updating Windows and check if the error is solved.

Update via Media Creation Tool

If Windows update KB5012599 is stuck during download at 0% or 99% or completely failed to install, then we suggest updating via Media Creation Tool. Follow the below steps to do so:

• Download Windows 10 installation media from the official Microsoft website.
• Open the tool once it is installed and then agree to license terms.
• Choose Upgrade this PC now and wait for the update to be installed

Install Windows Update manually

If nothing works for you and you’re stuck downloading the installed Windows updates then we suggest you install Windows updates manually. Follow the steps below to update Windows manually:

• Visit the Windows 10 update history webpage. You will find logs of all the previous Windows updates that have been released.
• Note down the KB number for the most recently released update.
• Then go to the Windows Update Catalog Website to search for the update specified by the KB number that you noted down.
• Download the update depending on your system which can be 32-bit = x86 or 64-bit=x64.
• You can get offline download links for these updates from here
• Open the downloaded file in order to install the update.

Note: As of 13 April 2022 – KB5012599 (OS Builds 19044.11645, 19043.1645, and 19042.1645) is the latest patch for Windows 10 versions 21H2, 21H2, and 21H2. KB5007189 (OS Build 18362.1916) is the latest patch for Windows 10 version 1909, and KB5007206 (OS Build 17763.2300) is for windows 10 version 1809.

Restart your system after installing the update.

Check your system’s space

Make sure your Windows-installed drive that’s C: drive has enough disk space to download and install Windows updates. Here’s how you can manually check for windows updates:

• Press Windows key + X and select settings.
• Click on Update & security and then hit the check for updates button.
• Make sure to click on the download and install link under optional updates (If available)
• Doing this will start the download and install windows updates from the Microsoft server.
• Restart your system to apply windows updates.

This brings us to the end of our guide on how to fix KB5012599’s failing to install on Windows. Did any of these solutions help you fix the problem? Let us know in the comments below. If you face any other errors while browsing, do let us know in the comment section.