Windows 11 August 2025 Cumulative Update KB5063878: Full Report, Issues, and Microsoft’s Response

Microsoft rolled out the Windows 11 August 2025 Cumulative Update (KB5063878) aiming to deliver security patches and performance improvements. However, shortly after its release, user reports surfaced about SSD malfunctions, UAC permission errors, and streaming issues.

This article provides a neutral, fact-based overview, combining user experiences, official investigations, and statements from hardware partners to help you understand the situation clearly.

Overview of the KB5063878 Update

The KB5063878 cumulative update was released in August 2025 for all supported Windows 11 versions. Its goal was to address security vulnerabilities and system bugs.

While the update initially appeared stable, a wave of user complaints soon emerged across forums, social media, and enterprise IT channels, raising concerns about storage reliability and system stability.

Reported Issues After Installing KB5063878

1. SSD Errors and Potential Data Loss

Many users reported drive errors, corrupted partitions, or unreadable SSDs after applying the update.

• Drives showing as RAW in disk management

• Sudden I/O errors or disappearing SSDs during large file transfers

• Performance drops during heavy workloads

Technical forums highlighted that these issues seemed more common when SSDs were over 60% full or when hibernation and Fast Startup were enabled.

References:

• Windows Latest

• Microsoft Q&A Community

2. UAC Permission Problems

Another widely reported issue involved the User Account Control (UAC) system.

• Applications that typically ran without administrator rights—such as AutoCAD, Civil 3D, and Inventor—started demanding elevated privileges.

• In schools and workplaces, non-admin accounts became unable to run critical productivity software.

• Error 1730 commonly appeared when trying to launch affected applications.

3. Streaming and Broadcasting Glitches

Live streamers and content creators also encountered performance problems with OBS Studio and other broadcasting software after the update.

• Screen capture stuttering

• Audio-video desynchronization

• Distorted or broken audio output

Many creators submitted feedback through the Microsoft Feedback Hub, urging for an immediate fix.

Microsoft’s Initial Response

Microsoft acknowledged the reports and provided temporary guidance:

• Uninstall KB5063878 if you are experiencing UAC errors or streaming issues.

• Wait for a corrective patch, which the company promised would be released after further investigation.

This immediate advice helped some users temporarily resolve operational disruptions.

Investigation and Official Findings

On August 31, 2025, Microsoft released its investigation results, clarifying that the KB5063878 update does not directly damage SSDs.

Microsoft’s Statement

• After extensive testing and collaboration with SSD and HDD manufacturers, no evidence was found linking the update to SSD hardware failures or data loss.

• The company committed to ongoing monitoring and further investigation of any credible new cases.
  Reference: The Verge

Phison’s Independent Tests

Phison, a major SSD controller manufacturer, conducted a rigorous validation process:

• Over 4,500 hours of continuous testing

• 2,200 automated cycles across multiple SSD models

• Simulated environments with different usage conditions

Results confirmed no reproducible failures, supporting Microsoft’s conclusion that the update poses a very low risk when drives are used under proper conditions with stable power and cooling.
References:

• PC Gamer

• Windows Central

Current Recommendations for Users

If you are experiencing problems after installing KB5063878, consider these steps:

• Uninstall the update to restore normal functionality for streaming or software affected by UAC bugs.

• Follow standard SSD maintenance practices such as keeping firmware up to date, avoiding sudden power loss, and ensuring proper cooling.

• Submit feedback through the Microsoft Feedback Hub with details of your system setup and error logs to assist with troubleshooting.

For users not experiencing any issues, there is no urgent need to uninstall the update, according to both Microsoft and SSD vendors.

Ongoing Monitoring and Next Steps

Microsoft has signaled that fixes for UAC and streaming problems are in development and will likely be released in an upcoming patch.

The situation also highlights the complexity of cumulative updates, where interactions with different hardware configurations can sometimes lead to unexpected bugs. Industry experts have emphasized the need for:

• More extensive testing before updates are rolled out broadly

• Clearer communication channels for reporting and tracking issues

Key Takeaways

• No confirmed widespread SSD damage has been linked to KB5063878.

• Issues with UAC permissions and streaming applications are acknowledged and pending official fixes.

• Monitoring and feedback remain essential as Microsoft works toward a resolution.