CPU Hot-Add Option Is Grayed Out on a Virtual Machine

Products

• VMware vSphere ESXi

Issue/Introduction

• Unable to increase CPU on the virtual machine from the VM Edit settings
• Although CPU hot-add is enabled, the option to add CPU remains greyed out.
• Virtual machine is configured with multicore virtual CPUs.
  
  
  
  
  
  

Environment

vSphere ESXi 7.x
vSphere ESXi 8.x

Cause

Hot adding multicore virtual CPUs is supported only with virtual machines that are compatible with ESXi 5.0 or later.

Resolution

To resolve this issue, upgrade VM hardware to the latest compatible version

Upgrading a virtual machine to the latest hardware version (multiple versions)

Upgrade the VM Hardware Compatibility of Virtual Machines

Additional Information

Enable CPU Hot Add