Follow below steps to recover data from an unmounted EDB file:
This message comes up when either Outlook is not installed on the system or if Outlook is installed, then it is not configured properly.
If Outlook in not present, install Outlook on the system where software is running.
If Outlook is present, then make a new POP profile in Outlook (it can be a dummy non working one). Uninstall and reinstall the software and then try again and it´ll resolve your issue.