Instead of having to search through your Inbox to figure out who accepted or declined the meeting invitation you sent out, let Outlook do the work for you. In a few simple steps, you can get a full listing of all invited attendees and their corresponding response to the invitation.
1. Go to your Outlook Calendar.
2. Find the desired meeting and double-click it.
3. Go to the Ribbon.
4. In the Show section, select Tracking.
A list will appear, detailing each person that you invited plus their response.