How can I stop Acrobat Reader opening my Powerpoint files?

Q  My Powerpoint presentation file icons have changed to Adobe Reader. If I right-click and choose Properties, the dialogue box says the file is a .pps (Powerpoint Slideshow) file, but that it is opened with Adobe Reader.

However, if I try to open one of these files, Adobe Reader says that it cannot open a .pps file. To try to work around this problem, I have been using the Open command from within Powerpoint and accessing the files that way. This seems to work.

If I then save the file, it opens again once more from a double-click on the icon (I then delete the old .pps file that still wants to open with Adobe Reader). However, I have hundreds of affected Powerpoint files, so correcting things this way is very time consuming.

Can you advise how this may have happened and if there is a way to correct all the files at once? My PC runs Windows XP.
Reg Austin

A  This is a common problem caused by incorrect file associations. Basically, Windows uses the three-character (and more recently four-character) extension after the file name as a guide to what program should be launched in order to open that file.

However, these extensions need the correct associations to be in place – essentially a little database that Windows keeps to tell it that file extension X should be opened with program Y.

We can’t say for sure why this particular file association was changed, though such problems are often the result of having installed new software (as some applications change existing file associations, though not usually without the user’s say-so).

Fortunately, the problem is easily fixed – though we should explain why opening the affected files directly in Powerpoint before resaving appears to fix the problem. In fact, this is a bit of an illusion.

A .pps file is a particular type of Powerpoint file that is designed to automatically start the slideshow when it is double-clicked. You have used Powerpoint’s Open command to open one of these files and then resaved it – but in doing so, you created a .ppt file, instead of a .pps file.

The .ppt file format is Powerpoint’s default file-save format and it is safe to assume that the .ppt file association remains intact. We can deduce this because you say that, having saved the new file, you then delete the ‘Adobe file’ (the .pps). If you were saving again as a .pps file, there wouldn’t be two files with ostensibly the same name.

As it happens, you were only one click away from resolving the problem. Having right-clicked an affected file to view its Properties dialogue box, a click on the Change button alongside the Opens With entry would have opened the Open With dialogue box.

From here, either select Powerpoint from the Programs list (if it appears) or click the Browse button, navigate to the Powerpoint program file (its precise location depends on the version of Office and the way it was set up but C:\Program Files\Microsoft Office is a good place to look), click to select it and click Open.

Make sure the ‘Always use the selected program to open this kind of file’ box is ticked and click by OK followed by OK and all .pps files will once more be associated with Powerpoint.