VMware Virtual Machine Running Windows Server 2025 encounters BSOD After Hot Adding CPU

Products

• VMware vSphere ESXi 7.0
• VMware vSphere ESXi 8.0

Issue/Introduction

On a virtual machine running Microsoft Windows Server 2025; the guest operating system will display BSOD and will restart automatically, when the system settings are configured as:

• On the virtual machine running Windows Server 2025, CPU Hot Plug is enabled
• vCPU is added from VM Edit Settings -> CPU on the vSphere UI
• In System Properties, the Automatically restart when System failure option is enabled

The virtual machine's vmware.log file, prints the following logs:

2024-03-02T17:37:20.784Z Wa(03) vcpu-0 - WinBSOD: Synthetic MSR[0x40000100] 0xa
2024-03-02T17:37:20.784Z Wa(03) vcpu-0 - WinBSOD: Synthetic MSR[0x40000101] 0x0
2024-03-02T17:37:20.784Z Wa(03) vcpu-0 - WinBSOD: Synthetic MSR[0x40000102] 0x2
2024-03-02T17:37:20.784Z Wa(03) vcpu-0 - WinBSOD: Synthetic MSR[0x40000103] 0x0
2024-03-02T17:37:20.785Z Wa(03) vcpu-0 - WinBSOD: Synthetic MSR[0x40000104] 0xfffff8043f868ebb

You may encounter this issue when you hot add a vCPU to a virtual machine running Windows Server 2025.

Resolution

This is a known Windows Server 2025 operating system issue. This issue is resolved in the update July 30, 2024—KB5040529 (OS Build 26100.1301) Preview - Microsoft Support.

Additional Information

The VMware Guest Operating System Installation Guide > Windows Operating Systems > Windows Server 2025, provides instructions to install guest operating systems.