[German]Microsoft is investigating reports that the cumulative security update KB5063878 released on August 12, 2025, for Windows 11 24H2 is causing serious SSD problems. At the same time, Redmond is asking those affected to report the issue.
KB5063878 and reports of SSD problems
On August 12, 2025, cumulative update KB50638 78for Windows 11 24H2 was released. The update includes quality improvements and security patches (I reported on this in the article Patchday: Windows 10/11 Updates (August 12, 2025)).
Subsequently, reports emerged from Japan that this cumulative security update KB5063878 can cause serious SSD problems. When transferring large amounts of data, reproducible errors occur when saving to certain SSDs with certain controllers. This can lead to data loss.
- The error pattern: SSD drives are no longer recognizable for Windows 11 24H2 (the S.M.A.R.T. values can no longer be read).
- Although it is sometimes possible to access the buffered directory structure of the medium, the associated files cannot be read.
The problem occurs in Windows 11 24H2 when writing large amounts of data to certain SSD storage devices. In tests conducted by the user, the problem occurs with SSDs with a utilization rate of over 60% after approximately 50 GB of continuous write data transfer.
According to user tests, Phison's NAND controllers are more prone to these malfunctions. Among these controllers, models without DRAM are more susceptible to malfunction at lower write volumes. A list of potentially affected SSD models can be found in this tweet.
Is there any truth to this?
Since I mentioned these reports in the blog post Windows 11 24H2: Does the Aug. 2025 update KB5063878 cause SSD errors?, there has been much speculation about what is going on in the German edition of this blog post.
On x, I had an exchange with another blogger who noted that he only knows of reports from Japan and suspects that it could be related to specifics of the Windows version in question.
Readers have reported suspicious incidents, but it is unclear whether this is related to SSD firmware issues. Blog reader Bolko added further information about affected SSDs from various sources in the comments section of the German blog post Windows 11 24H2: Führt Aug. 2025-Update KB5063878 zu SSD-Fehlern?
Microsoft and Phison are investigating
Bolko wrote in this comment (source) that Phison is analyzing the problem. However, firmware updates will not be provided directly by Phison. Any firmware fixes will be passed on to SSD manufacturers. They will then release customized firmware for end customers.
As far as I know, there has been no official statement from Microsoft yet, but our colleagues at Bleeping Computer write in the above tweet and in this article that, according to a spokesperson, Microsoft is "aware of these reports and is investigating them together with our partner."
NAND controller manufacturer Phison also told Bleeping Computer that it is working with Microsoft to resolve the issue. "Phison was recently made aware of the industry-wide impact of updates KB5063878 and KB5062660 for Windows 11, which may have affected several storage devices, including some supported by Phison," a Phison spokesperson is quoted by Bleeping Computer as saying. He continued: "We are aware of the potential disruption this may have caused and have immediately engaged with industry stakeholders. [..] We are currently reviewing the controllers that may be affected and are working with our partners."
Microsoft requests feedback
In this article, Bleeping Computer reports that Microsoft is requesting further information from customers who have experienced issues with failures and data corruption on their solid-state drives (SSDs) and hard disk drives (HDDs) after installing the August 2025 security update.
Customers should contact business support or use the feedback hub to submit a report. No reports have been submitted to customer support yet.
Similar articles:
Microsoft Security Update Summary (August 12, 2025)
Patchday: Windows 10/11 Updates (August 12, 2025)
Patchday: Windows Server Updates (August 12, 2025)
Patchday: Microsoft Office Updates (August 12, 2025)
Windows 11 24H2: Update KB5063878 causes installation error 0x80240069
Windows 11 24H2: KIR fix for WSUS installation error 0x80240069 with update KB5063878
Windows 11 24H2: Update KB5063878 as a re-release for WSUS (August 14, 2025)
Windows 11 24H2: Does the Aug. 2025 update KB5063878 cause SSD errors?
Windows 10 support ends in two months and they are leaving us with this crapware OS! Well done microsoft! Some things never change…