You have a sub-report that works pulling back data. You change it to display “multiple columns” either horizontal or vertical and the data disappears on the screen.
Once you choose “Format with Multiple Columns” a new tab called “Layout” will appear on the “Section Expert” for the “Details” section. Click on the “Layout” tab and make sure that the width is greater than 0. For some reason, mine always defaults to 0 with Crystal Reports 2011 (v14). You’ll want to set the value to be high enough to display the data you want to display.