I have a report with breaks on a data value. When I fold the report, it insets page breaks after every break value. I now have too many pages, with lots of white space. How can I prevent Webi from doing that?

In the standard "Quick View" when looking at your report, it will look like there is a lot of blank space after each break, and page breaks inserting after almost every break value.

Try this: save your report, then open it in InfoView. Go to the View menu.
Select Page mode from the drop-down choices in the View menu. Your report should now appear correctly collapsed to the minimum number of required pages.
Also, if you do a Save As... to Excel, the report will remain in the collapsed view.