PPS files are PowerPoint Slide Show files created by Microsoft PowerPoint, although unlike PPT files they are not editable, according to File Info. If you don’t have Microsoft Office for your Mac, opening PPS files can be a bit of a problem. However, Keynote, the presentation creating software that comes with the Apple exclusive program iWork, can open PPS files on a Mac without a problem as long as you change part of the file extension.
Click on the PPS file once and wait for a couple of seconds. Click on the file again so the text is highlighted. Click in the text field and erase the extension “PPS.” Add the new extension “PPT.” Click “Use PPT” when a dialogue box pops up.
Open Keynote on your Mac computer. Keynote is in your dock or the Applications folder. Double-click on the icon to open it.
Select “Open” from the File menu and choose the PPT file from your Mac. Click “Open." Keynote will open the file like a regular PPS file.