Does Optimizer change my PowerPoint file?
Optimizer always works on a copy of your original PowerPoint file, so other than saving your file again then closing it, Optimizer doesn't touch your valuable original presentations.
Optimizer saves your original as "OPT" + the original file name; it saves this file to the same folder as your original presentation.
For example, if you open C:\Presentations\MyShow.PPT and optimize it, you'll now have two files:
C:\Presentations\MyShow.PPT and
C:\Presentations\OPTMyShow.PPT