Unable to convert a VMware virtual machine snapshot to a memory dump

Products

• VMware vSphere ESXi

Issue/Introduction

Converting a VMware virtual machine snapshot to a memory dump with vmss2core.exe fails with the following error :

Unrecognized .vmss file (magic 4f434e45)

 

Example:

#vmss2core.exe -W8 snapshot.vmsn snapshot.vmem
vmss2core version 8456865 Copyright (C) 1998-2017 VMware, Inc. All rights reserved.
Unrecognized .vmss file (magic 4f434e45).

 

 

Environment

VMware vSphere 8.x

Cause

This issue occurs because the virtual machine is encrypted.

When a snaphot with memory is taken, vmem file is also encrypted.

Resolution

• Decrypt VM 

Decrypt an Encrypted Virtual Machine or Virtual Disk

• Convert the snapshot file to memory dump with  vmss2core tool

https://knowledge.broadcom.com/external/article?articleNumber=181598

• Re-encrypt VM

Encrypt an Existing Virtual Machine or Virtual Disk