Is your thesis one with a lot of diagrams, illustrations and tables like mine?
Unless you are a formatting whiz, a lot of people have trouble making sure that their text looks right after they insert a photo, diagram or table. Instead of inserting the object at the beginning, keep it out until your last round of proofreading, if you are editing on paper, just put a sticky note where you want the corresponding object and keep track of the numbers. That way if you switch the position of two objects, their numbers will match up in your list of diagrams.
Another alternative is to take a brief online Microsoft word tutorial on setting up indexes if you don't want to edit on paper, you can train your computer to update your table of contents for you, but don't rely on it, always have your final editor check to make sure all objects match the table of contents, are properly labelled and in order.