This is a converted version of the master slide from the PPT deck, so the size of it is tied to the amount and type of objects on it. If there are images on the master slide, make sure they are not large, hi-res images that were re-sized in PPT to fit the slide. Properly resizing images in an application like PhotoShop can greatly reduce the file size of your presentation.
Thank you for your answer. I had actually discovered the Master File in this PowerPoint presentation. It would help to know that I did not create this presentation, nor am I fully experienced in Powerpoint. I am learning as I go along, though.
So, I discovered the Master Slide had an image as the background, and it seemed to be a large resoultion image. It also seemed to be fully covered up by the content of every slide. I think that the creator of this presentation uses this as his master slide and just covers it if he doesn't want it showing. At any rate, I changed the image to a simple color gradient and saved it. Saving took several seconds. When I go back to the slide master, I can see no trace of the image.
However, exporting a new presentation did not result in a master file (in the data folder) that was any smaller. It was exactly the same, in fact. I think that Presenter has the content stuck in its memory and wont let go.
Do you know how I might totally re-set the master slide in PPT to make sure the master file in Presenter does not come out so large? Is there perhaps any other info that is contained in the master file?
I have alleviated the problem by changing my output setting from high quality to medium. The master file comes out at 2,000 kb. Still much larger than others, but at least it doesn't take a minute to load.