I only got the message 'Sync pending for this folder' in the bottom right of the screen next to the Connected status. Last Friday, I was running Outlook for Mac 2011 and I had an issue where my Inbox wouldn't sync. I am an Outlook for Mac user with a MacBook Pro and using Office 365 for our Exchange hosting.
All, I've found several topics CLOSE to my issue, but none that fit it perfectly.