I get this error when opening pptx file in C#:
Can’t read MSCDFileSystem
The file is ZIP archive. It can be Microsoft PowerPoint 2007 PPTX presentation.
LoadOptions lo = new LoadOptions();
lo.Password = base.password;
pres = new PresentationEx(documentStream, lo);
Sample file is attached. Kindly note that it happens when there is no password (ie lo.Password is assigned blank ""
PresentationEx ppsd = new PresentationEx(file);