Aspose.Slides for .Net throws a NullReferenceException when trying to save the attached .pptx file input.zip (22.8 KB) as .ppt using the following code:
var input = @"<...>\input.pptx"; var presentation = new Presentation(input); presentation.Save(input + "_save.ppt", SaveFormat.Ppt);
Observed this on versions 19.11.0 and 18.10.0 as well.
The file was created using Ms PowerPoint 2016 by simply adding a ComboBox content control to the first slide of a new presentation and leaving it empty.
Thanks for any help!