New Backup: After denoting source & before Destination T.I. 2015 goes to 100%

After selecting the files for a new backup and before selecting a destination, the system goes into 100% usage. There is a little dot under the : "Folders and Files" image in a 'reloading' circle. At one time, I believe I saw a "Calculating size" message. I have let this run for as much as three hours before stopping it.

Build: 6525
Update: 12/15/14