Unless you shut them down from vCenter you won't see an event for the power off. I guess you could analogously look for something like the memory usage state change, or parse through the VM log. I think to concretely get this you'd have to go through the OS log. Or maybe going forward make a note on the machine description about shutdown date.

Good luck!

You do have to parse the events. This should get you started on what you're looking for:

$vmlist = Get-VM | Where {$_.PowerState -eq 'PoweredOff'}
ForEach ($vm in $vmlist){
  $vm | Get-VIEvent -Types Info | Where {$_.fullFormattedMessage -match "Powered Off"} | `
  Sort-Object -property createdTime |  select -last 1 | %{
  Write-Host $_.vm.name $_.createdTime | Out-Default}
}

The above assumes you've already done connect-viserver etc.

But this will only give you the VMware events, they won't give you OS power operations, hence my comment about looking for analogous events.

From my testing - vcenter records a state change whether the shut down comes from console/RDP session or right-click within the VM client. Event retention could be a problem depending on how busy the environment is - say if weeks or months go by.

Afaik these are two different events, capture both.

Something like this.

You'll notice that a GuestOS shutdown generates both types of events.

So ultimately you should only look for the VmPoweredOffEvent