Outlook 2011 hangs (spinning beach ball) when adding or saving an attachment

Outlook 2011 hangs (spinning beach ball) when I try to add or save an attachment via the Open/Save Dialog Boxes.  The list of folders in the left column of the Dialog Box does not populate, then the spinning beach ball pops up.  Have to Force Quit and then restart.  If I add an attachment by dragging from a Finder window in to a draft email, that works.

No problems with the Open/Save Dialog Boxes in other apps, including Word, Excel, OSX Mail etc.

I've run Disk Utility from the OSX Recovery mode, no problems found with the disk.

OSX 10.9.4, Office for Mac 2011 14.4.3, MacBook Pro 2010