There's no really easy answer to this question without more information. In general, Seagate Info/Crystal Reports writes Crystal Reports best in Crystal Reports format.
If you need to export to a different format such as MS Excel, then you need to specifically design the report so that it exports correctly. The easiest way to do this is to ensure that all fields are contained within guidelines.
Depending on the layout of your report, you may also need to experiment with the various Excel export settings (if you use the extended versions).