Microsoft has addressed several critical bugs causing installation, upgrade failures, and Blue Screen of Death (BSOD) issues on high-core-count Windows Server 2025 systems.
Affected devices were experiencing failed or stalled installations, extended boot and restart times of up to three hours, and occasional blue screens when starting or running applications.
These issues, while not consistently triggered, predominantly affect systems with over 256 logical processors. Microsoft advises checking the Task Manager’s Performance tab (CTRL+SHIFT+ESC) to see if your system is impacted.
The issues were resolved in the cumulative update KB5046617, released on November 12, 2024. Microsoft recommends applying this update to ensure your server benefits from all necessary security fixes and improvements.
For administrators unable to immediately install the KB5046617 update, Microsoft suggests a workaround:
- Enter UEFI Setup: Restart the server and navigate to the UEFI firmware settings.
- Adjust Logical Processors: Locate an option to limit cores per socket and set a value ensuring the total logical processors stay at 256 or fewer.
- Reboot: Save changes and restart the server.
Microsoft also notes that they are working on a fix for another issue in Windows Server 2025 affecting systems in iSCSI environments, which may result in “boot device inaccessible” errors.
Windows Server 2025, now available as Microsoft’s latest Long-Term Servicing Channel (LTSC) release, includes a free 180-day trial through the Microsoft Evaluation Center.
