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Exception "Value cannot be null" is thrown when re-open a PPT file using Aspose Slides for .NET


I’m using Aspose Slides to try to reload a ppt file after saving it, but when I do that, exception was thrown with 2 types of exception: " Value cannot be null.\r\nParameter name: key"" and “object reference not set to an instance of an object”.

My sample code:

    FileStream fStream = new FileStream(original_ppt_file, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
    fStream.Seek(0, SeekOrigin.Begin);
    Presentation presentation= new Presentation(fStream);
    presentation.Save(temp_file, SaveFormat.Ppt);
    fStream = null;
    fStream = new FileStream(temp_file, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
    fStream.Seek(0, SeekOrigin.Begin);
    presentation= new Presentation(fStream);

The exception will be thrown when I try to re-load the temp file using presentation.

I tried to upgrade Aspose Slides to lastest version: but the issue still be there.

Here is my sample: sample.zip (3.8 MB)

Please check and give me some advices.


Dung H. Nguyen


I have observed the issue shared by you and an issue with ID SLIDESNET-40779 has been created in our issue tracking system to further investigate and resolve the issue. This thread has been linked with the issue so that you may be notified once the issue will be fixed.

Hi @Adnan.Ahmad,

Is there any update for this question?


I have observed your comments. I like to share this issue is going to be resolved tentatively in Aspose.Slides 19.2. I request for your patience.