How to fix
KB5015878 fails to install
on Windows

Hello, I have tried installing KB5015878 as I saw that it fixed the bug where the troubleshooter would not open (the problem I am dealing with, unfortunately). I came to another dead end now, as the update simply won't install. I am really annoyed by this, so I hope there's something you could help me with regarding this issue.

By default, Windows is set to install updates automatically as soon as the computer is booted and is connected to the internet. This is not a coincidence, as keeping your system up to date can be vital - updates patch various security vulnerabilities, fix bugs, implement new features, and improve stability and performance.

Microsoft operates Windows as a service, which means that it ships new improvements regularly. To be more precise, patches usually arrive on the second Tuesday of every month, hence the process has been named "Patch Tuesday" for many years now. There are also several types of updates - cumulative, feature, security, and others.

KB5015878 is one of the newer updates that was released to the Preview Channel on May 18, 2022,[ref en-3] which is dedicated to those who participate in the Windows Insider Program.[ref en-1] This allows users to check out new features earlier than the rest and allows them to send feedback that Microsoft can use to change things.

The update included a lot of new features, such as the ability for users to consent to receive urgent notifications when focus assist is on, as well as bug fixes such as troubleshooter not opening. Unfortunately, just like any other Windows update, KB5015878 fails to install for some users.

Luckily, there are a few solutions that could help users fix these installation problems. Before you proceed with the manual instructions below, we recommend running a scan with [d1] - a repair solution that can automatically fix common Windows issues, including BSODs,[ref en-2] DLL errors, update failures, and more.

Fix 1. Use the built-in troubleshooter

Troubleshooters are excellent built-in tools that Microsoft offers for free. They can perform s scan that looks at the particular problem and attempts to find the reason for the issue, and offers solutions as well. Therefore, we recommend starting by running Windows Update Troubleshooter.

• Type Troubleshoot in Windows search
• Select Additional troubleshooters
• Find Windows Update from the list
• Click it and select Run the troubleshooter
• Once the download is finished, apply the suggested fixes and restart your computer.

  

Fix 2. Perform SFC and DISM scans

System file corruption can always be one of the main reasons for Windows update failures. Thus, make sure it is not the case by following these steps:

• Type cmd in Windows search
• Right-click on Command Prompt and pick Run as administrator
• When User Account Control shows up, click Yes
• Use the following commands, pressing Enter after each of the lines:
  sfc /scannow
  DISM /Online /Cleanup-Image /CheckHealth
  DISM /Online /Cleanup-Image /ScanHealth
  DISM /Online /Cleanup-Image /RestoreHealth
• Restart your system.

  

Fix 3. Set to automatic startup type or restart BITS and Windows Updates services

• Type in Services in Windows search and press Enter
• Locate Background Intelligent Transfer Service (BITS)
• If it is already running, right-click and select Restart
• if the service is not running, double-click it, select Automatic under the Startup type from the drop-down menu
• Click Start, Apply, and OK
• Now locate Windows Update Service and perform the same steps.

  

Fix 4. Reset Windows Update components

• Open Command Prompt as administrator, as we explained before
• Copy and paste each of the command lines, pressing Enter after each and waiting till each of the commands is executed properly:
  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
• Restart your computer and attempt to update Windows once again.

  

Fix 5. Reset your internet connection

In case your internet connection is unstable, it could result in Windows updates failing. Try resetting your connection:

• Open Command Prompt as administrator again
• Paste in the following commands, pressing Enter after each:
  ipconfig /flushdns
  ipconfig /registerdns
  ipconfig /release
  ipconfig /renew
  netsh winsock reset
• Restart your PC.

Fix 6. Temporarily disable or uninstall third-party security software

Security software might sometimes interfere with the process of Windows updates, for example, it may blacklist one of the servers that the updates are being downloaded. Therefore, if you are using third-party anti-malware software, you should disable or uninstall it and try running the update once again.

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