Module CPUID power on failed. Failed to start the virtual machine. The current EVC mode is masking features SSE 4.1 SSE 4.2 POPCNT required by rhel9-64 guests. This virtual machine cannot be powered on.

Products

• VMware vSphere ESXi 8.0
• VMware vSphere ESX 7.x
• VMware vSphere ESX 8.x

Issue/Introduction

Not able to power on linux VM on a particular cluster.

You try to power on rhel9-64 VM

You get below error:-

"Module CPUID power on failed. Failed to start the virtual machine. The current EVC mode is masking features SSE 4.1 SSE 4.2 POPCNT required by rhel9-64 guests. This virtual machine cannot be powered on"

Environment

ESXI 7.x

EVC enabled on cluster with baseline:- Merom

Cause

You’re running into the fundamental fact that RHEL 9 64-bit guests require CPU instructions (SSE 4.1, SSE 4.2, POPCNT) that the Merom EVC baseline deliberately hides—so the VM simply won’t power on under Merom.

Resolution

Option 1:-

Raise EVC baseline. – RHEL 9’s needed features only start showing up at the Intel Nehalem baseline (SSE 4.2 + POPCNT). – Preconditions: every host in the cluster must have at least a Nehalem-generation CPU. – Steps:

1. Migrate or power off all VMs on the oldest hosts.

2. In vSphere Client → Clusters → Configure → vSphere EVC → Edit → select Intel EVC: “Nehalem” or higher.

3. Wait for the cluster to finish the EVC re-configuration, then retry powering on.

Option 2:

Move the VM into a cluster whose EVC baseline is already Nehalem (or newer). – If you have mixed-generation hardware, segment older hosts into their own Merom-only cluster and leave newer hosts in another.