I have worked with the presentation files shared by you using Aspose.Slides for .NET 6.3.0 and have not been able to observe any issue in accessing the presentations. I have used .NET 4.0 version dll of Aspose.Slide for .NET in Windows 7 x64 environment. Please share, if you need any further help in this regard. The sample project and generated output are shared for your kind reference.
I have found the problem. There is some incompatibility with VS 2010 feature “Tools-> Options -> Debugging-> General -> Enable .NET Framework source stepping” and Aspose.Slides. Maybe because of your library obfuscation. I can live with disabled feature.
I have the same problem but I do not have VS 2010 feature “Tools-> Options -> Debugging-> General -> Enable .NET Framework source stepping” set. I’ve attached my PPTX in case there is an issue with it, but it opens fine in Powerpoint 2010.
I have worked with the presentation file shared by you and have not been able to observe the issue in accessing the presentation using Aspose.Slides for .NET 6.7.0. For your kind reference, I have also attached the generated PDF as well. Please share the sample project with us if there is still an issue.