Crystal is VERY picky about format when exporting to Excel. In order to get a "clean" export you need to do the following:
1. Make sure that ALL of your column headers are the same height have the same number of lines after they word-wrap in Crystal. For example, when some column headers wrap to two lines and other don't, I frequently will add a carriage return (Enter key) before the text on the ones that are one line so that the text appears at the bottom of the header.
2. DO NOT USE LINES!!! Lines will not export but will add extra blank, thin rows and columns to your report.
3. Your data and your header for each column MUST be the same width and MUST line up exactly (select the objects and use the right-click, Align menu option to make this happen.
4. Use guide markers for your columns so that you can line your objects up so that there is no space between them. This also makes it easier to align everything.
If you're on FaceBook, I've written a longer "how to" that's available as a note from the SAP Crystal Reports and Dashboard Design fan page. I can't access FaceBook from work, so I am unable to give you the link to it.
-Dell