​Microsoft has confirmed several bugs causing install and Blue Screen of Death (BSOD) issues impacting Windows Server 2025 systems with more than 256 logical processors.

Users may experience symptoms such as Windows Server 2025 installation or upgrading processes failing or hanging and server starting and restarting taking as much as three hours or more in some cases.

They might also see blue screens when launching, restarting, or attempting to run an app on impacted servers.

However, as the company explains in a new Windows release health entry, these issues are not triggered consistently on affected devices.

To determine if these known issues impact one of your Windows Server 2025 systems, open the Windows Task Manager using the CTRL+SHIFT+ESC keyboard shortcut and check if it shows over 256 logical processors on the Performance tab.

Redmond is working on a fix, which will be delivered with an upcoming Windows monthly update. Until a resolution is available, admins can work around these issues by limiting the number of logical processors on affected devices to 256 or under.

To adjust how many logical processors are active, you can follow these instructions:

1. Restart your server and enter the UEFI Setup. Navigate through the firmware menus, which may vary by manufacturer.
2. Locate any option which allows you to adjust the number of cores per socket.
3. Set the number of cores per socket to a value that ensures the total number of logical processors is 256 or fewer. Important: The total number of logical processors is calculated by first multiplying the number of sockets by the number of cores per socket and then multiplying that result by the number of logical processors per core.
4. Restart the server.

It also warned customers that they might see some text appear in English during installation when using certain media, such as CD or USB, to install Windows Server 2025, regardless of the selected language.

This only occurs when using the Multilanguage User Interface (MUI) on Windows Server media 25100.1742 and later.

Microsoft released the first Windows Server 2025 build for admins in the Windows Insider program in January, introducing next-gen Active Directory, hotpatching, and SMB over QUIC alternative ports, which allows switching from the default SMB over QUIC UDP/443 port to any other port.

The company announced over the weekend that Windows Server 2025 is now generally available, with a free 180-day trial available via the Microsoft Evaluation Center.

Windows Server 2025 is now Microsoft’s latest Long-Term Servicing Channel (LTSC) release for Windows Server.