Hello Rich Sousa,
Thanks for your message.
Our
Free Spire.Xls will not create the warning sheet, you should be using our paid version(
Spire.XLS Pack(Hotfix) Version:12.6.1) which will generate the warning sheet without applying a valid license.
Since our Free version is limited to 5 sheets per workbook and 200 rows per sheet. This limitation is enforced during reading or writing XLS or PDF files. From Free Spire.XLS v7.8, there is no any limitation when loading and saving .xlsx file format. When converting Excel files to other formats, such as PDF/XPS/Images, you can only get the first 3 pages of PDF/XPS/Images. If your file exceeds the limitation, you can keep using our paid version. We are willing to provide a temporary license (one month free) to help you remove the warning message. If you need it, please feel free to let us know.
Sincerely,
Simple
E-iceblue support team