Hi, Devisri,
Thanks for your prompt reply & assistance.
I was able to successfully use Insert() with the EssentialPresentation.pptx that you supplied, and noted that it was created with Office 365 (internally v. 16.x). I was also able to create a new .pptx using Office 2013, read it, clone a slide, insert it into the presentation, save the presentation, and read it successfully using Office 2013.
http://superuser.com/questions/664355/which-version-of-powerpoint-was-used-to-create-a-document and http://portal.presentationpro.com/kb/a192/how-do-i-tell-what-version-office-powerpoint-my-computer.aspx were useful in determining internal version numbers of the .pptx files with which I'm working.
I have only Office 2013 (internally version 15.x) and that is also the version used to create the attached AnonymizedOffice2013Template.pptx.
So, it appears you supposition about the possibility of content inside the template .pptx is likely correct. Can you examine AnonymizedOffice2013Template.pptx and/or work with it to reproduce what I'm seeing?
Thank you,
Brian
Attachment:
AnonymizedOffice2013Template_f11eeec0.zip