Latest Windows 11 security patch might be breaking SSDs under heavy workloads — users report disappearing drives following file transfers, including some that cannot be recovered after a reboot

Microsoft’s latest security update for Windows 11 is allegedly causing SSD failures during heavy file transfers. The issue was reported by X user Nekorusukii @Necoru_cat, who was updating Cyberpunk 2077 on a system running Windows 11 24H2 with the KB5063878 update installed, when the SSD on which the game was installed disappeared from the operating system.

An investigation by the user reveals a potential bug that appears during continuous file transfers on certain storage devices, particularly when the transfer exceeds 50GB and the drive is over 60% full. In these cases, the SSD can sometimes disappear from within the operating system. While restarting the PC makes the SSD visible again, the issue seems to occur again as soon as a large data transfer is performed again.

It was earlier reported that the issue lies within how SSDs handle cache, especially DRAM-less models equipped with Phison NAND controllers, but it turns out the problem isn't confined to those types of drives. A series of tests was carried out to establish the scope of the problem, which included copying Cyberpunk 2077's Steam library folder to the drive, preparing a compressed archive, and then copying the expanded archive into the target storage.

Out of the 21 drives tested, it was found that 12 of them became inaccessible, but only the Western Digital SA510 2TB could not be recovered even after a reboot. This indicates that the issue seems to impact SSDs with multiple types of SSD controllers.

Nekorusukii has listed the complete findings and explains that the SSDs were tested only on his own system, so the results may not offer enough proof on the real-time performance of these drives. Additionally, they do not assert that the Windows 11 24H2 KB5063878 or the previously released KB5062660 updates are directly responsible for the issues. However, a separate report by Japanese outlet NichePCGamer has further identified at least eight users on X who are facing similar issues on their respective drives.

According to a user with a SanDisk Extreme Pro M.2 NVMe 3D SSD, the drive became inaccessible after installing a 50GB update for Honkai: Star Rail. Although restarting the system resolved the issue, the user encountered it again on multiple occasions in August. Suspecting the KB5062660 update as the cause, the user deleted the update file, after which the problem no longer occurred.

By the looks of it, the issue doesn’t seem to be widespread. While we wait for Microsoft and SSD manufacturers to acknowledge the bug, it is best to stay cautious, especially if you are dealing with large continuous file transfers on systems running the latest Windows 11 KB5063878 update. We've reached out to Phison specifically regarding the issue, but the company wasn't immediately available for comment.

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