Here's my scenario.
I have 2 .pptx files. Each has 1 slide.
I would like to take the slide from the 1st .pptx file and insert into the other.
I have read several articles, posts, etc and tried to implement but they all have errors.
When I open it, I see the other slide but with no content and I get the File Repair dialog.
I've used the diff util and it shows a lot of missing/different elements.
Since a slide can refer to other elements that are outside the slide itself, all those need to be copied. In some cases, the copy is not simple. For example, what if your layouts and master are different between the two presentations?
I don't know of any examples that handle any slide copy. If you do not need a general purpose solution, then you probably just need to track down the references in your particular slide and make sure those are copied. It will take some work.
You can refer this thread. It tells how to copy slides from multiple presentations into a single one. You can find help there.