The August 2025 Patch Tuesday update for Windows 11 24H2 KB5063878 has been an eventful one for sure. As is usually the case with Windows monthly Patches, they are not bug-free and this one in particular has caused major headaches. Aside from NDI OBS streaming issues and Windows installer failures, users reported that their NVMe SSDs were running into problems like disappearing from Windows and potentially even corrupting the data when large amount of data is dealt with.
Following our report, Phison stated that it was looking into the problem as it appeared that some of its controllers were affected. About a week and a half later, the firm released its report after the investigation. However, affected users were left disappointed as Phison stated that it could not replicate the problem even after dedicating 4500 hours of thorough testing.
Soon enough Microsoft showed its own hand, reiterating what Phison had found, that it too did not see any link between drive failures and the August Patch.
Despite this there were murmurs around on social media that perhaps something escaped the testing of both Phison and Microsoft as some users continued to report similar problems on their SSDs.
Of course keep in mind that it is entirely possible that certain NVMe SSDs did indeed fail, but those had nothing to do with the Windows 11 24H2 update, and it was just a coincidence that they happened at a time when this report came out.
Finally though we may have some answers. A Chinese Facebook PC DIY enthusiast group named PCDIY! appeared to have discovered what the actual root cause of the issue really is. It appears that the real cause of the problem is pre-release versions of engineering firmware that somehow may have been triggered by the Windows 11 updates that led to the problems.
The PCDIY! group admin Rose Lee also claims that the issue was successfully verified by Phison engineers in the labs and this gives credibility to the report. Lee writes (Google-translated to English from Chinese):
PCDIY! testing has revealed that the SSDs crashing and crashing due to the Windows 11 update were using pre-release, pre-final versions of the engineering firmware. Because all SSD manufacturers selling products using PHISON controllers purchase their products from the original manufacturer and ship them in bulk using mass-production tools, the SSDs delivered to consumers are already using the official firmware. The official firmware has been thoroughly tested and verified, and does not exhibit the anomalies often seen with engineering firmware.
Thus it appears that anyone who purchased an NVMe SSD from a retail store should not have to worry as the final production firmware of drives do not have this issue, which is why Phison or Microsoft did not find any problems during their testing as it is likely only retail-ready products were tested.
If you are, however, encountering troubles of a similar nature then it is worth doing a firmware update on your SSD; but do ensure to back up your data before, just in case.
Phison has also added that the issue of the slowing down of drives is due to maxing out the SLC cache when running large data transfers. In such cases, users would need to run a Secure Erase to fix slowdown issues and a Windows format is simply not enough.
Source: PCDIY! (Facebook)
Thanks for the tip, Aryeh Goretsky!!!!
Update, September 8 2025, 7.50 GMT: Phison responded to our report on this issue with its official statement.