What is a PPSX file?
PPSX, Power Point Slide Show, file are created using Microsoft PowerPoint 2007 and above for Slide Show purpose. It is an update to the PPS file format that was supported by Microsoft PowerPoint 97-2003 versions. When a PPSX file is shared with another user and opened, it starts as PowerPoint show unlike PPTX file that opens in editable mode. The sequence of slide show is the same as in the original presentation. All the slides accompany the images, sounds and other embedded media accompany the presentation slides to the PPSX during the slideshow.
File Format
PPSX files are created in Office OpenXML file format and share the same structure as PPTX. Based on zipped XML file format, it adheres to the specifications outlined in MS-PPTX file format document. In order to open the PPSX files in editable mode, these need to be opened from within Microsoft PowerPoint.
PPSX files are saved in the Open XML format, which was introduced in Microsoft Office 2007. They may be opened by PowerPoint 2007 or later, or by earlier versions of PowerPoint with the Open XML component installed. Complete details about the PPSX file format can be found in the MS-PPTX specifications document that equally apply to PPS as well.