.xlsb file in DocumentFormat.OpenXml.Packaging throwing error of OpenXmlPackageException: 'The specified package is not valid.'

Question

.xlsb file in DocumentFormat.OpenXml.Packaging throwing error of OpenXmlPackageException: 'The specified package is not valid.'

Answer 1

Hi @Mahenoor Mahida

The Open XML SDK is better discussed on the following sites:

https://stackoverflow.com/questions/tagged/openxml-sdk
https://github.com/dotnet/Open-XML-SDK/issues

Your question is specifically answered on:

https://github.com/dotnet/Open-XML-SDK/issues/617

The .xlsb file extension is an ISO 29500-2 OPC (Open Packaging Convention) package like the .xlsx, .docx and .pptx, however, the contents of the workbook, worksheet, etc... parts is not SpreadsheetML (i.e. XML) but Excel's binary format. Therefore it is not supported by the Open XML SDK which only supports WordprocessingML, SpreadsheetML and PresentationML (and DrawingML). Files with the .xlsb extension follow this file format specification:

[MS-XLSB]: Excel (.xlsb) Binary File Format

Hope this helps.

Best regards,
Tom Jebo
Microsoft Open Specifications Support