In the old days (PPT 95 through 2003), the only difference between a presentation and a show was the extension. So if you had a presentation and wanted it to open in slideshow view, just the file extension had to be renamed. But in the new world (now 2 years old) of PPT 2007 that does not work.

1. Here is our test file – a .pptx (PPT 2007 presentation)

2. Manually change the file extension (.pptx), changing the “T” to an “S”, and Windows gives this confirmation dialog

3. The icon changes to the PowerPoint Show icon and the extension is .ppsx

4. But when you try to open the file you get this error

5. Why? Because any Office 2007 file with an “x” in the file extension is really a .zip file with lots of individual files inside it. Changing the extension does not directly change the file any longer, so the quick fix of ‘just rename it’ no longer works…

– Troy @ TLC