Microsoft can’t confirm Windows 11 KB5063878 causes SSD failures despite user reports

• Some Windows 11 users report SSD and HDD failures after installing update KB5063878, but Microsoft and Phison say they cannot reproduce the issue.
• These companies report no confirmed failures in testing or telemetry, though Microsoft is collecting user feedback while advising caution.

Although many users have reported failures and data corruption affecting Solid-State Drives (SSDs) and Hard Disk Drives (HDDs) after installing the Windows 11 24H2 security update KB5063878 (build 26100.4946), Microsoft and Phison remain unable to reproduce the issue.

Microsoft says it cannot reproduce the problem

Shortly after the release of the August 2025 Security Update (KB5063878), reports began emerging of a critical storage problem where SSDs and HDDs would disappear under sustained write loads of roughly 50GB or more. However, after repeated attempts to replicate the problem, Microsoft told media outlets it has been unable to reproduce the issue.

The company also noted that neither internal testing nor telemetry data shows any increase in storage failures or corruption. In addition, Microsoft’s support team has not received any direct customer reports. Still, the company is actively collecting feedback from affected users to identify the root cause and says it will share details as soon as they become available.

However, the Windows Release Health page also indicates at least two known issues with this update, including severe stuttering, lag, and choppy audio and video on streaming apps such as OBS and NDI Tools (confirmed), as well as Error 0x80240069 when installing the update through the Windows Server Updates Service (resolved).

Phison’s testing shows no failures

Phison has also released a statement confirming it tested the drives allegedly affected. After more than 4,500 cumulative hours and over 2,200 test cycles, the company has not been able to reproduce the failure. Similarly, Phison states that no partners or consumers have directly reported the issue.

The company also suggested that misinformation may be contributing to the confusion, as some reports circulating among customers contained inaccurate data. Media outlets highlighting Phison-based drives as the most affected appear to have relied on unclear or unverified tests.

Users continue to report mixed experiences

Despite this, user reports of storage issues continue to surface, but it remains unclear whether this is indeed related to the specific update or if the storage failure for some users is merely a coincidence and unrelated to other problems.

I recently uploaded a new video tutorial with the steps to uninstall the update KB5063878 from Windows 11 24H2, and many users have reached out expressing their frustrations with this release.

For example, some users reported that their external drives disappeared but were restored intact after uninstalling the update and restarting their computers. Others, however, claimed the disappearance resulted in permanent data loss.

At the same time, some users with allegedly affected drives reported experiencing no issues after installing the update. This points to a mixed and inconsistent experience following KB5063878.

On Reddit, you can find numerous reports on this topic, and you will also notice mixed responses, with some reports indicating problems, but also mentioning specific configurations that may have caused the issue.

Additionally, in the Windows 11 community on Reddit, a user reported that their device stopped working immediately after installing the update in question.

What you should do if you installed KB5063878

For now, the safest course of action is to pause or disable automatic updates until Microsoft provides clarity. If the update is already installed, consider uninstalling it and pausing Windows Update. If you choose to keep the update, avoid transferring large files or filling drives beyond half of their capacity.

Regardless of your approach, the most important step is to have a recovery plan that includes a full backup of your files and system.

If you have additional information or want to share your experience, drop it in the comments.