I have an application that consumes Excel workbooks (.xlsx). My workbook created with M365 produces the error “corrupt openxml document” when consumed by the app but when I copy the data from the original workbook to a new workbook using Excel 2016 32-bit, the application consumes the workbook fine. The application is using SpreadsheetGear 2012.

I tried saving the workbook that worked with M365 Excel and this cause the issue.