How to fix
KB5063878 installation failure
on Windows 11

KB5063878 keeps failing to install on my Windows 11 PC. I’m on 24H2, it downloads, reboots to ~30%, then rolls back with 0x80240069. I’ve tried "Retry" a few times and even paused/resumed updates. How do I install KB5063878? KB5063878, released on August 12, 2025, is the latest cumulative security update for Windows 11 version 24H2, bringing the OS build to 26100.4946. While most devices apply it without trouble, some users encounter situations where KB5063878 fails to install, the update keeps rolling back during setup, or it gets stuck partway through. In certain cases, you might notice KB5063878 failing to install repeatedly over several attempts, or Windows Update showing it as pending without progressing. Some users also encounter an issue where the update fails with a persistent 0x80240069 error code. The error code 0x80240069 typically relates to Windows Update services being unable to authenticate or connect to Windows Update servers. These problems usually aren’t the result of a single bug in the update itself. More often, they’re caused by issues on the device - such as insufficient disk space, corrupted system files, damaged Windows Update components, or conflicts with drivers and security software. Network interruptions or failing to meet certain prerequisites can also lead to KB5063878 not installing correctly. The good news is that most of these installation errors can be fixed without reinstalling Windows entirely. The steps below walk through proven solutions, from quick checks to more advanced repairs, to help ensure KB5063878 installs successfully. If you prefer a faster route, you can also use the automatic PC repair tool to address the problem automatically.

Fix 1. Run the Windows Update troubleshooter

The built-in troubleshooter can detect and fix issues preventing KB5063878 from installing.

1. Type troubleshoot in Windows search and press Enter, or go to Start > Settings > System > Troubleshoot.
2. From the list of Options, pick Other troubleshooters.
3. Scroll down to locate Windows Update and click Run.
4. Wait for it to finish, then apply changes and reboot the system.

Fix 2. Check services

1. Type in Services in Windows search and press Enter.
2. Locate Windows Update Service.
3. If it is already running, right-click and select Restart.
4. If the service is not running, double-click it to open Properties.
5. Under the Startup type, select Automatic from the drop-down menu.
6. Click Start, Apply, and OK.
7. Locate Background Intelligent Transfer Service (BITS), Cryptographic service, and Windows Installer service, and repeat the process.

Fix 3. Reset Windows Update components

1. Type in cmd in Windows search.
2. Right-click on Command Prompt and select Run as administrator.
3. User Account Control window will show up - click Yes when prompted.
4. Stop the Windows Update Services by entering the following commands, one at a time, and pressing Enter after each: net stop wuauserv net stop cryptSvc net stop msiserver net stop bits
5. Rename the SoftwareDistribution and Catroot2 folders with the following commands: ren C:WindowsSoftwareDistribution SoftwareDistribution.old ren C:WindowsSystem32catroot2 catroot2.old
6. Restart the services you stopped earlier with these commands: net start wuauserv net start cryptSvc net start msiserver net start bits
7. Close the Command Prompt window and try updating Windows again.

Fix 4. Check disk space

Insufficient disk space can prevent updates from installing. Ensure there is at least 20GB free.

1. Navigate to Settings > System > Storage.
2. Review available space on all drives. If space is low, consider deleting unnecessary files or moving data to an external drive.
3. Empty the Recycle Bin and remove Temporary Files using Disk Cleanup.

Fix 5. Disable third-party antivirus software

Third-party antivirus software can interfere with Windows updates. Temporarily disable it during the update process.

1. Locate your antivirus icon in the system tray.
2. Right-click and select Disable or Pause protection.
3. Choose a time frame that covers the update process.
4. After the update, re-enable your antivirus to maintain protection.

Fix 6. Perform Disk Cleanup

1. Type Disk Cleanup in Windows search and hit Enter.
2. If your Windows is installed on drive C, pick it from the list (it should be by default) and press OK.
3. Click Clean up system files.
4. Select your main disk again and click OK.
5. Select the largest portions of the data used - these typically include Temporary Internet Files, Windows Update, Temporary Files, Recycle Bin, Delivery Optimization Files, and others.
6. Click OK - the process should be finished shortly.

Fix 7. Run the System File Checker and DISM

1. Open Command Prompt as administrator.
2. Copy and paste the following command, pressing Enter after: sfc /scannow
3. Wait till the scan is finished. If Windows finds system file integrity violations, it will attempt to fix them. After this, use the set of the following commands, pressing Enter each time: DISM /Online /Cleanup-Image /CheckHealth DISM /Online /Cleanup-Image /ScanHealth DISM /Online /Cleanup-Image /RestoreHealth
4. (Note: if you get an error executing this last command, add /Source:C:RepairSourceWindows /LimitAccess to it and try again).
5. Close down the Command Prompt and restart your computer.

Fix 8. Install the update manually

1. Go to the official Microsoft Update Catalog website.
2. Type the KB number into the search bar (in this case, KB5063878), and click Search.
3. 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).
4. After picking the correct version, click the Download button and proceed with the on-screen instructions.
5. Restart your computer to implement the new updates.

Fix 9. Use Media Creation Tool

The Media Creation Tool can be used to perform an in-place upgrade, which can help bypass certain update errors by reinstalling Windows 11 while keeping files and applications intact.

1. Visit the official Microsoft website and download Windows 11 installation media.
2. Double-click the installer and select Yes when UAC shows up.
3. Agree to terms.
4. Select Upgrade this PC now and select Next.
5. Windows will now download all the necessary files – it might take a while.
6. Agree to the terms once again and click Next.
7. Before installing, ensure you are happy with your choices (otherwise, you can click the Change what to keep option).
8. Click Install to begin the upgrade process.

Fix 10. Work around 0x80240069 errors with Known Issue Rollback (KIR)

Microsoft has acknowledged that some enterprise-managed devices encounter 0x80240069 when installing KB5063878 via WSUS. A Known Issue Rollback (KIR) policy is being rolled out, but administrators can apply it manually to affected devices.

1. Download the Known Issue Rollback Policy [direct download link].
2. On the affected device or domain controller, open Group Policy Editor (gpedit.msc) or Group Policy Management Console for domain policies.
3. Navigate to the policy path where the KIR setting is provided for Windows 11 version 24H2.
4. Enable the KIR Group Policy provided by Microsoft for KB5063878.
5. Apply the policy to the targeted devices (either via local policy or domain-wide).
6. Restart the affected devices to ensure the setting takes effect.
7. Once applied, try installing KB5063878 again.