Recent reports of SSD failures following the installation of the Windows 11 update KB5063878 sparked concerns among users, but Microsoft has concluded its investigation and found no connection between the update and the reported issues. The company, along with SSD controller manufacturer Phison, conducted thorough testing to determine if the update was indeed responsible for the drive failures.

Initial reports surfaced in mid-August 2025, with users describing sudden SSD failures during heavy data operations, particularly when transferring large files (50GB+) to drives that were over 60% full. These reports, primarily originating from Japan, pointed to the KB5063878 security update as a potential cause. Affected systems were running Windows 11 24H2 and had recently installed the update. Some users reported that their drives disappeared, while others experienced file corruption, with reboots failing to resolve the problem. Popular SSDs from Corsair, SanDisk, and Kioxia, many of which use InnoGrit or Phison controllers, were among those reportedly affected.

In response to these reports, Microsoft launched an investigation and worked with storage device partners to reproduce the issue. However, their internal testing and telemetry data did not reveal any increase in disk failures or file corruption after installing the Windows 11 24H2 security update. Microsoft stated that it found no connection between the August 2025 Windows security update and the reported hard drive failures. The company also mentioned that its customer support teams had not received reports of customers experiencing this issue.

Phison, a manufacturer of SSD controllers, also conducted an extensive testing campaign, dedicating over 4,500 hours to the drives reported as potentially impacted and conducting more than 2,200 test cycles. Phison also stated that it was unable to reproduce the reported issue, and no partners or customers had reported that the issue affected their drives at this time.

Despite the findings of Microsoft and Phison, some users continue to report SSD failures after installing the KB5063878 update. It is important to note that SSDs, like all storage devices, are susceptible to failure due to various reasons, including wear and tear, physical damage, power surges, firmware corruption, overheating, and manufacturing defects. Other factors, such as bad sectors, virus damage, short circuits, and corrupt data, can also contribute to SSD failure.

Given the conflicting information, it is advisable to monitor SSD health, especially when writing large files on drives that are more than half full. Users can also report any issues to their drive's manufacturer and to Microsoft to help establish a clearer understanding of the situation. While Microsoft has refuted the link between the Windows 11 update and SSD failures, it is still essential to exercise caution and take necessary precautions to protect valuable data.