This is a limitation of 64,000 lines in the Excel version used by Crystal Reports.  If the report is over the limits, run the report for smaller date ranges and/or use filters to decrease the length and perform multiple exports to export all information.

For non-reporting exports, Excel 2007 and higher can handle 1,048,576 rows by 16,384 columns per Microsoft website (if available system memory supports this)

We are unable to address this issue because it is related to third-party software. Contact Microsoft for assistance.