Case "Execution time"

Hi all,

I simply need to "stamp" a case with the exact date & Time that it was resolved.  I cannot seem to achieve this.

I added a field formatted as Date & Time

Set a workflow to trigger if the status changes, the workflow then did this:

The action:

However, when the case is resolved, the field is never updated with the execution time, this happens (Nothing):

Any ideas?

Many thanks

David