Setting Virtual Machine Latency Sensitivity to High fails with error "Failed to reconfigure virtual machine a specified parameter was not correct: spec.memoryAllocation"

Products

• VMware vSphere ESXi

Issue/Introduction

• Upgrading Cisco virtualized applications, prerequisite - virtual machine's RAM needs to be increased at VM sensitivity level normal 
  
  
• Reverting virtual machine sensitivity to high, fails with error "Failed to reconfigure virtual machine a specified parameter was not correct: spec.memoryAllocation"

Environment

• VMware vSphere ESXi 8.0.3

Cause

Memory reservation not set for the VM.

Resolution

• Reserve all guest memory i.e. setting 100% memory reservation on the VM. See Configure the virtual machine latency sensitivity 

Note: It is by design that High Latency Sensitivity requires you to set CPU and 100% memory reservation for the VM.