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Issues trying to compare certain files of certain extension types



I’m getting the error when trying to compare certain .doc and .pptx files.

Further details are below:
‘Groupdocs.Comparison.Exceptions.ComparisonException’ occurred in Groupdocs.Web.UI.Comparison.dll but was not handled in user code

Additional information: Operation ’ ’ failed: Cannot open document.

A Zip with the files is attached for reference. Thanks in advance for the support.




We are sorry to hear that you have such issue. If we understand you right and since in the package you shared one .doc file and one .pptx file we can assume that you tried to compare .doc with .pptx, sorry but comparison allows comparing documents only of the same type, for example: .doc with .doc, pdf with pdf. Since that please choose documents of the same type for comparing.

If you will have more question please feel free to contact us.


Thank you for the response. I was definitely not comparing a .doc to a .pptx. The two files in the Zip folder fail on their own during any Compare process.

The software allows for Comparison of a file to itself and that’s one way to test out the attached. You can also try to compare the files in the .zip to any other .doc or .pptx with the same result.

Thanks again. Please let me know if you need any more information.


Hello J,

Thanks for the clarification. Yes, you are right, GroupDocs.Comparison cannot open these two files “Standard Invoice 2 - 006j0000002cSzy.doc” and “Standard Invoice 2 - 006j0000002cSzy.pptx”, which can be found in the ZIP archive. We are able to reproduce this exception, it seems that this is a bug inside a GroupDocs.Comparison. The development team is already notified and working on it, when there will be any news about this issue, we will notify you in this forum thread.

Thanks and sorry for the inconvenience.


Thanks Denis.

We’re looking forward to an update!