There has been news in the latter half of August that Windows update KB5063878 has reportedly been killing SSDs, especially when performing continuous file writes exceeding 50GB on a drive that’s at least 60% full. However, after more than a week of investigation, Microsoft confirmed that the aforementioned update was not the cause of the issue. According to Redmond’s resolution to the service alert related to the original report, “After thorough investigation, Microsoft has found no connection between the August 2025 Windows security update and the types of hard drive failures reported on social media.”
One user claims that the bug affects how SSDs handle cache, and that models without DRAM and Phison NAND controllers are the most heavily affected. However, their further testing of 21 different SSDs revealed that drives using controllers from other brands seem to be affected as well. Nevertheless, the drives that crashed or disappeared were reportedly recovered after restarting the system, save for the Western Digital SA510 2TB model they tested.
Although the issue does not seem to be widespread, more drama came out when a document containing a list of Phison controllers that were supposedly affected by the problem was widely circulated. The company vehemently denied that the file came from it and said that it would take legal action against the original leaker of the data. Nevertheless, it continued testing, and after 4,500 hours, it stated that it could not reproduce the issue. Still, Phison recommends that users with heavy storage workloads install heatsinks on their SSDs if they haven’t already done so to reduce the chances of thermal throttling.
A few days after this, Microsoft also released its conclusion that there’s no connection between the failed drives and the security update. It claimed that there was no increased risk of disk failure or file corruption after doing internal testing, and telemetry data also did not yield any meaningful results. Aside from that, the company claimed that no customer has reached out directly to its support teams with this same issue.
Both Phison and Microsoft basically say that they cannot reproduce the issue, with the latter concluding that there was no problem with the update. Nevertheless, we still see a few posts on social media saying that their drive died after installing KB5063878. We’re unsure whether this is a pattern or a mere coincidence, especially considering the millions of SSDs in circulation. After all, we’ve seen big companies deny that there’s anything wrong with their products only for us to discover later that there’s a major issue with them (like Intel’s instability issues).
In the meantime, you should monitor your SSDs, especially if you’re writing large files in a storage drive that’s more than half full. And if you experience the same problem, it’s best to report it to both your drive’s manufacturer and to Microsoft so that we can establish a paper trail. That way, we can determine what’s really going on with the drives and the security update.
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