Outlook 2011 for mac showing 2 unread messages but I can’t find them

This all started yesterday.  The icon for outlook showed an unread count and the inbox showed the same number.  I have subsequently cleared the inbox but still it shows an unread count.  I have searched for unread mail but none can be found. 

I've checked on my web view of the same account and there are no unread messages there. 

I have tried restarting outlook and rebooting the mac but these have made no difference. 

What has changed and I don't know why is that the doc icon no longer displays the incorrect unread count but the GUI still does. 

Any ideas what I should do. 

Thanks