Take sequential backup of your PowerPoint presentations.
Sequential Save is a simple add-in for your PowerPoint. This add-in will add a button to the Standard toolbar, every time you click on that button, it will create a backup of the last saved version on the disk and then will save the existing file. You can either create a single backup file or multiple sequential backups. The add-in does not delete any presentation nor does it change the original presentation in any manner.