I have four to five My Book external hard drives (12–14 TB each) connected to my home and office desktop computers. Recently, these drives have started failing to be recognized upon reboot—one at a time, rather than all at once. Each time I restart, a different drive stops appearing.
The error message I receive points to wdcsam64.sys, which I assume is the driver for these hard drives. I have attempted to update the driver, but my computers indicate that it is already up to date. Both of my computers are running Windows 11, and I have confirmed that the OS is fully updated. I have also tried uninstalling and reconnecting the drives multiple times, but the issue persists.
After further research, Microsoft suggests disabling Core Isolation, but doing so triggers warnings about potential security vulnerabilities, which doesn’t seem like a safe or practical solution. This issue is occurring on two separate computers in different locations, and based on online discussions, it appears that many other My Book users are experiencing the same problem.
The root cause seems to be related to Western Digital’s wdcsam64.sys driver. However, the common advice—updating the driver—does not resolve the issue. Is this a driver-related problem? If so, how can I obtain and properly install an updated version?
For reference, I connected an older Seagate drive to my home computer, and it functions without any issues.
