Sometimes I would be able to view PowerPoint (.pps) documents with Quick Look, but sometimes I wouldn't. This problem bothered me for some time, but I think I've solved it -- thanks to the helpful folks on this forum thread (in French).
The solution involves editing the Office Quick Look generator file; read on for the how-to...
Here's what I did:
- Navigate to /System » Library » QuickLook » Office.qlgenerator. Control-click on the generator and pick Show Package Contents from the pop-up menu. Then navigate to Contents.
- Create a copy of info.plist to use as a backup.
- Open info.plist with TextEdit or your favorite text editor.
- Scroll down to find the following text:
- Replace all of that with this:
- Save the new plist file and quit the editor.
- Navigate to your user's Library » Preferences folder, and trash com.apple.QuickLookDaemon.plist.
- Open the Terminal application and type qlmanage -r, and press Return.
[robg adds: I haven't tested this one.]

