Revert ESXi 5.5 VM Hardware Upgrade

So you’ve upgraded ESXi and vSphere to version 5.5. Next you’ve logged into your ESXi server and upgraded your Virtual Hardware on your VM’s as you have done with every other ESXi upgrade. Not so fast there HOTROD, you go to edit your VM settings and find that you are no longer able to do so using vSphere. You vaguely start to remember a warning(pictured below) that you didn’t read prior to upgrading your VM hardware. This is probably the point where you begin to slightly panic, of course you always have the backups. You tell yourself, restoring from backup will take time and you really don’t want to have to do that. Fortunately for you there is a way to revert back to the previous VM hardware version without a restore.  Keep reading below.


So here are the steps to fix the problem without having to restore your backups.

  • Turn off the VM and note the datastore your VM’s running under.
  • Unregister the VM — “remove from inventory” on the host.
  • Browse the datastore and download the VMX file.
  • Edit the VMX in notepad and change virtualHW.version = “10” — back to 8 (or 9 if you’d like to upgrade to the 5.1 hardware).  Save the file.
  • Browse back to the datastore.  I’d recommend renaming the original VMX as a backup.  Upload your edited VMX.
  • Click the “Add VM to inventory” button to re-register your edited VMX to the host.
  • All should be good now.  If so, delete your backup VMX file.
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