Thanks for your posting and using Aspose.Cells.
We were able to observe this exception after running your sample code with the latest version: Aspose.Cells
for .NET v22.214.171.124.
We have logged this issue in our database for investigation. We will look into it and fix this issue. Once, the issue is resolved or we have some other update for you, we will let you know asap.
This issue has been logged as
- CELLSNET-43292 - Exception on saving workbook with empty chart sheet
Thanks for your using Aspose.Cells.
Please download and try the latest fix: Aspose.Cells for .NET v126.96.36.199 and let us know your feedback.