The latest Windows 11 update is suspected to be the cause of SSD and HDD disconnection issues during large data transfers. Although many users in Japan have reported drives disappearing while copying data, manufacturer Phison—one of the most popular SSD controller providers—stated they could not reproduce this error after thorough testing.
Response from Phison and the SSD error investigation process
Immediately after Microsoft released the KB5063878 update for Windows 11 24H2 on August 12, there were numerous reports from users in Japan that SSD and HDD drives became unrecognizable after performing large data transfers exceeding 50GB. In most cases, restarting the computer helps restore the drive, but the issue recurs during other data copying operations. Some drives even require formatting or repartitioning to function normally.
Following the wave of complaints, Phison was the first in the industry to announce they are cooperating with Microsoft to investigate. However, in a report sent to Wccftech, Phison stated that after 2,200 test cycles and over 4,500 hours of performance measurement, they did not record any errors as described. At the same time, the company recommends that users attach a heatsink to NVMe SSDs to reduce the risk of thermal throttling, although the phenomenon is believed to be not entirely related to temperature.
Phison also refuted allegations that their SSD controllers have compatibility issues with the new update. A document circulating online alleging serious errors related to the company’s drive lines was denied by Phison as fake. As of now, although the cause has not been identified, Phison remains the only one among storage manufacturers to officially speak out about this incident.
Users should be cautious when updating to KB5063878
In addition to official investigation efforts, many other users, especially from the tech community in Japan, continue to encounter similar issues after updating. The Twitter account @Necoru_cat—the first to discover the problem—is currently communicating directly with Microsoft to clarify the cause. They also denied neglecting heatsinks, further strengthening the hypothesis that the issue may lie in the software, not the hardware.
Besides Phison, many drive lines from Samsung, Western Digital, Seagate, Corsair, and Crucial have also been reported to encounter similar errors, especially when storage usage exceeds 60% of the total drive capacity. However, these manufacturers have not yet officially announced the aforementioned situation.
While a specific conclusion has not been reached, users running Windows 11 version 24H2 should consider delaying the KB5063878 update or limiting large data transfers, especially with drives operating at high temperatures or those that are nearly full.
Operating system updates are necessary to ensure security and performance, but it is also important to assess actual risks, especially with patches that may affect hardware. Please follow information from manufacturers and Microsoft for the most appropriate way to handle your system.
