HELP:Export to Excel error for large data

[mars_wu]

When I export CR to Excel with large data, all the cells merge disappeared after row 20K. The first 20K rows looks perfect. (20K here is not the exact number, but around that area)
Any idea why this happens?

[jggtz]

Too many rows for excel
Once in excel, what is the next step to take with the data?

[mars_wu]

Excel (2003) can have up to 65K rows, is it 20K rows too many?
Users just use excel export file to review, and I have checked with them, they don't want other formats, like PDF, which doesn't have any problem.