GroupDocs pdf comparison not working


Thanks, Do let us know if you have any findings. The application is not usable because of this.

Is there a way to escalate this issue other that a Paid Support. As I think this is not a case of Support.
Rather a Show stopper in your Product.

Please provide any email, numbers to contact directly!



Sure, we will update you.

As there are number of other issues in queue. You have to avail the priority support in order to expedite the process.
However, we shall surely notify you as we have any update on it.



We are pleased to inform you that your reported issue is now resolved in version 18.9. We can successfully compare the problematic files (source and target) you shared with us.


Hi Atir,

From where can i download the latest version.



You can download latest version here.


Hi Atir,

We have tried referring the new dll you have provided. But compiling set of reference error comes. We have removed the old service reference and added the new service reference you have provided. See the screenshots for error details.GroupDocsCompileError1.png (35.6 KB)
GroupDocsCompileError2.png (21.6 KB)



As you migrated from version 3.3.0 to 18.9. There were number of back-end API changes. We’d recommend you to update your project. Please download/clone our examples project from here and follow the namespace references. This example project is updated/managed as per latest release (v18.9).
Furthermore, please refer to the release notes in order to see API changes.


Hi Atir,

I downloaded the example project and tried incorporating the changes by updating our project. It seems only docx and xlsx file comparison is working and for pdf its getting null exception. For xlsx comparion its taking too much time. Please provide the dll where all available file types can be compared with at least 30 days trial period so that we can do POC and test all scenarios.




We investigated this issue using problematic files you shared in the private message. We can successfully compare source and target PDFs using following code:

// Get instance of GroupDocs.Comparison.Comparer and call method Compare.
GroupDocs.Comparison.Comparer comparison = Common.getComparison();
ICompareResult result = comparison.Compare(Path.Combine(Common.sourcePath, Common.sourceFile), Path.Combine(Common.targetPath, Common.targetFile), new ComparisonSettings());
// save result document to a file.
result.SaveDocument(Path.Combine(Common.resultPath, Common.resultFile));

Can you please share the xlsx files with us?

Please note that using GroupDocs.Comparison for .NET 18.9 DLL you can process all possible comparison operations (e.g. pdf to pdf, xlsx to xlsx).

When you compare docx files, do you get an evaluation mark in the output file?

Please note that if you properly load or apply the license, you can avail all API (document comparison) features without any limitation. Otherwise, you may face these evaluation limitations.


Hi Atir,

See the below code in our Project:

GroupDocs.Comparison.Comparer comparison = new GroupDocs.Comparison.Comparer();

ICompareResult result = comparison.Compare(Path.Combine(Server.MapPath(curUserFolder), sourceFileName), Path.Combine(Server.MapPath(curUserFolder), targetFileName), new ComparisonSettings());

result.SaveDocument(Path.Combine(Server.MapPath(curUserFolder), diffFileName));

This is how we implemented. But pdf comparison is not giving any result and null exception it give.

During comparison of docx files i am getting evaluation mark in output file. Does that mean our license is not valid?EvaluationMessage.png (51.1 KB)
We have a perpetual license which wont expire as mentioned earlier.

I am attaching the problematic pdf here.source and targetsource.pdf (390.0 KB)
target.pdf (462.9 KB)

For excel sheets with more than 3 sheets with large data takes time to compare.



We are investigating this issue. As we have further updates, we shall update you.



Please see subscription expiry date in your license file. As per that information, API versions that are released after the subscription expiry date are not consistent/compatible with the license.
We have same case here, the version 18.9 is released on 10/4/2018, so it cannot be used with your existing license.

As your license is perpetual, please note that license does not expire means that you will be able to use this license file forever with the versions released before the subscription expiry date.
In order to integrate and utilize v18.9 in your project, you may need to buy a new license. If you have any purchase related query, you can post here.


Can you please provide a Temporary License with full capabilities, so that we can ensure the issue is fixed for our problematic files ?



You can request a temporary license here. Following the wizard on step 5 you can get a temporary license.
Please go through this document as well - (152.9 KB)


Hi Atir,

I tried comparing docs with the new dll version from the below link:
It is version 18.10. Also added the new temporary license suggested by you. It is comparing almost all file types. But while comparing a large pdf file with another large pdf it is throwing null exception. Can you please check?
Null_Exception.jpg (429.0 KB)



Can you please share the problematic files (source and target PDFs) with us? We’ll then investigate the issue.


Hi Atir,

Please find the attached Source and Target files. Please check this to the earliest and let us knowSource.pdf (2.3 MB)
Target.pdf (2.0 MB)




Thanks for sharing the problematic files. We are investigating this issue at our end. Your investigation ticket ID is COMPARISONNET-1747. As we have any update, we shall notify you.


Hi Atir,

Any news about the large file issue. Its urgent for us



This issue is still under investigation. We shall notify you as we have any update.
However, if you want to escalate the issue, you may avail priority support.