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Not able to convert PowerPoint to PDF - urgent

We are getting “The license is not valid for this product” error while converting a PowerPoint file to PDF, whilst using a valid Aspose.Total for .Net license.

Mail, Word and Excel do work as expected.

We are using the following Nuget packages:

  • Aspose.Email => ok
  • Aspose.Words => ok
  • Aspose.Cells => ok
  • Aspose.Slides => NOT ok


I have observed your comments. Can you please share source files, source code, environment details and which Aspose.Slides version you are using on your end so that we may further investigate to help you out. Please also provide the license used on your end by following these guidelines.

Please find our source code below:

MemoryStream outputStream = new MemoryStream();

//Code to register Aspose license for Powerpoint
Aspose.Slides.License slidesLic = new Aspose.Slides.License();

//Convert PowerPoint Presentations to PDF
Presentation PresentationDoc = new Presentation(streamToConvert);
PresentationDoc.Save(outputStream, Aspose.Slides.Export.SaveFormat.Pdf);
return outputStream;

We are only using the Aspose package to convert presentations to PDF, as a helper method for other functionality.
The following code is being used in a .NET project (Target framework: .NET 4.6.1)

We are using this Aspose.Slides for .NET version: v17.8.0


I have observed your comments. Can you please share source presentation so that we can further investigate to help you out.

It is actually happening with all presentations…


As requested earlier, can you please provide the license used on your end by following these guidelines

Hi, I did send the license file through the message functionality to Adnan Ahmad. The option to send a regular mail as described in the article doesn’t seem to reflect the new UI of this forum… (see also image attached)2017-09-05_7-48-57.jpg (27.8 KB)

I will also send you the license file through the “Message” option.


I have worked with license file shared by you using Aspose.Slides for .NET 17.8 on my end and have not been able to observe any issue while using license file. For your kind reference, I have attached the sample project as well. Moreover, I have also attached the sample presentation and generated PDF as well. I hope this will be helpful.

TestSlides.zip (32.1 KB)
Presentation Data.zip (42.0 KB)


we were able to detect the root cause of the PPT conversion thanks to the solution you provided!

Thanks for your support,
Kind regards