This article was previously published under Q326736
When you try to download a PowerPoint Show (.pps) file from an Internet Information Server (IIS) server, you may receive a PowerPoint Presentation (.ppt) file instead of a .pps file.
NOTE: This problem only occurs on computers that have Microsoft Office installed.
This problem can occur because there is no registered Multipurpose Internet Mail Extensions (MIME) type for .pps files on either the IIS server or on the client computer. Because PowerPoint SlideShow (*.pps) files are associated with PowerPoint only by their file name extension, and not a separate MIME type, Microsoft Internet Explorer processes the file as a standard PowerPoint (*.ppt) file. Therefore, you are prompted with a .ppt extension when you save the file instead of a .pps extension.
To correct this problem, create a new MIME type on the IIS server that is specific for .pps files. To do this:
In IIS Administrative Console snap-in, right-click the specific Web server where the .pps file is located, and then click Properties.
Click the HTTP Headers tab.
Click the File Types button.
Click New Type.
In the Extension box, type .pps, and then in the Content type (MIME) box, type application/vnd.ms-pps.
Click OK, and then restart IIS.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.