Created attachment 33474 [details] This is the file that causes the exception After creating an empty workbook and creating a sheet, I close the workbook and use an existing FileOutputStream with the location of the workbook to create a new FileOutputStream, and try to write out using the XSSFWorkbook.write(File) method, and receive "Rule M2.4 exception" which says it should never happen and to submit a bug. Thanks, Paul
> use an existing FileOutputStream That might be the problem. Otherwise, your explanation sounds pretty much like standard, working code. Could you post an example of your code that demonstrates the problem?
No response, so closing WORKSFORME for now, please reopen with more information if this is still an issue for you.