Here is your Shake and Bake answer.

GO to your "Library" tab.
CLICK on "incomplete".
HIGHTLIGHT (single mouse click) on the TOP file.
SCROLL waaay to the bottom.
HOLDING DOWN THE SHIFT KEY, highlight the bottom file.

You with me so far??

All files should now be selected/shaded.

CLICK "RESUME"

You will be informed that any files you have finished and a lot of opther stuff. Make your choice according to your wants and wihes.

good luck