How Can Windows Server 2019 Update KB5063877 Fix Cluster Service Crashes?

Why Is My Windows Server 2019 Cluster Failing After July Updates? Understanding the August 2025 Update for Windows Server 2019

If you manage Windows Server 2019, an important update is ready for you. Microsoft released this update, known as KB5063877, on August 12, 2025. It fixes a significant problem that may have been causing issues in your server environment since July 2025. This article explains the problem, the solution, and what steps you should take.

The Main Problem: Cluster Services Kept Breaking

The primary issue fixed by this update relates to the Cluster Service in Windows Server 2019. The Cluster Service is a vital component that helps multiple servers work together as a team. This teamwork ensures that if one server has an issue, another can take over, keeping your applications and services running without interruption.

Starting in July 2025, after a previous update (KB5062557) was installed, this service began to fail. It would unexpectedly stop and then try to restart itself over and over again. This created a cycle of instability that could seriously impact your operations.

Administrators who experienced this bug noticed several key symptoms. These signs indicated that the cluster was not healthy.

• Servers Couldn’t Rejoin: A server that left the cluster group, either for maintenance or due to an error, could not get back in.
• Servers Were Quarantined: The system would sometimes isolate a server, thinking it was faulty, which prevented it from participating in the cluster.
• Virtual Machines Restarted: Virtual machines running on the affected servers might have been forced to restart multiple times, causing downtime for users.
• Error Logs Filled Up: The server’s event logs would frequently show errors with the Event ID 7031, signaling that the Cluster Service terminated unexpectedly.

This problem was most common in specific setups. It mainly affected servers that used both BitLocker drive encryption and Cluster Shared Volumes (CSV). CSV allows all servers in the cluster to access the same storage at the same time, which is essential for many high-availability setups. The combination of these features with the faulty July update triggered the bug.

What Caused This Mess?

The trouble started with update KB5062557 from July 8, 2025. After installing this update, cluster operations stopped working correctly. Microsoft confirmed this in internal documents.

Many IT professionals spent weeks trying to figure out why their servers kept crashing. The constant restarts made it nearly impossible to run stable operations.

How KB5063877 Fixes Everything

The new update KB5063877 targets the root cause. It stops the cluster service from getting stuck in restart loops. Your servers can now:

• Join clusters without issues
• Stay stable during normal operations
• Run virtual machines without unexpected restarts
• Generate fewer error messages in logs

Second Fix: Microsoft Changjie Input Method

The same KB5063877 update also corrects a different bug related to the Microsoft Changjie Input Method. This tool is used for typing traditional Chinese characters. While this issue may not affect a majority of users in English-speaking regions, it was a problem across many versions of Windows, including Windows 10, Windows 11, and other Server versions. The August 2025 updates have fixed this input method issue across all affected systems.

What You Should Do Now

To ensure your server environment is stable and secure, it is important to take action. Follow these simple steps.

1. Identify Your Systems: Check if you are running Windows Server 2019. Pay special attention to servers that are part of a failover cluster, especially if they use BitLocker and Cluster Shared Volumes (CSV).
2. Review Recent Issues: If you have noticed any of the symptoms described above, such as service restarts or virtual machine instability since July 2025, this update is likely the solution you need.
3. Deploy the Update: Schedule and install the cumulative update KB5063877. As with any update, it is best practice to test it in a non-production environment first before deploying it to all of your critical systems.
4. Verify the Fix: After installation, monitor your Cluster Service and event logs. You should see that the service remains stable and the Event ID 7031 errors related to the cluster have stopped appearing.

Applying this update is a key step to restore stability to your server infrastructure and prevent unexpected downtime.

Who Should Install This Update?

This update helps anyone running:

• Windows Server 2019
• Windows 10 2019 Enterprise LTSC
• Any system with cluster configurations
• Servers using BitLocker with CSV

Installation Is Simple

The update installs like any other Windows update. You can get it through:

• Windows Update service
• Microsoft Update Catalog
• Your usual patch management system

Why This Matters for Your Business

Server downtime costs money. Every minute your systems are down, your business loses productivity. This update prevents:

1. Unexpected server crashes
2. Lost work from virtual machine restarts
3. Time spent troubleshooting cluster problems
4. Emergency IT calls during off-hours

Expert Recommendation

Install this update as soon as possible. Test it in a development environment first if you have one. The benefits far outweigh any installation risks.

Your cluster services will become stable again. Your virtual machines will stop restarting randomly. Your IT team can focus on important projects instead of fixing broken servers.

Microsoft took two months to fix these problems. That’s a long time for businesses dealing with unstable servers. The good news is that KB5063877 addresses both issues completely.

Don’t wait to install this update. Your servers need this fix to run properly. Your business depends on stable IT infrastructure. This update delivers exactly what you need.