A file's "extension" is a sequence of characters added after the file's name and a period. Software producers design programs to save files with specific extensions for two reasons: The extension identifies the application used to create the file, and file management programs read the extension to know what program to use to open a file. In 2007, Microsoft Office introduced a new kind of file-saving system, XML, and a new set of extensions for PowerPoint documents made its debut.
XML File Benefits
Since 2007, extensions for PowerPoint files end with either an "m" or an "x," indicating a file saved as an XML file with or without macros, respectively. Saving files in what is called an "open XML format" creates a file that is more compact, more easily repaired in case of corruption of data, easier to protect, better able to integrate with other programs' data and faster to inform your software system of whether the file uses macros.
Files Ending in "x"
PowerPoint file extensions ending in "x" indicate XML files without macros enabled. The extensions are as follows: a presentation is ".pptx," a template is ".potx," a PowerPoint show is ".ppsx," a PowerPoint slide is ".sldx" and an Office theme PowerPoint is ".thmx."
Files Ending in "m"
PowerPoint file extensions ending in "m" indicate XML files with enabled macros, which are shortcuts that help with often-performed tasks. A ".pptm" is a macro-enabled presentation, a ".potm" is a macro-enabled template, a ".ppam" is a macro-enabled add-in, a ".ppsm" is a macro-enabled show and an ".sldm" is a macro-enabled slide.
Opening "x" and "m" Extensions in Older Versions of PowerPoint
To open newer PowerPoint files in PowerPoint 2000, XP or 2003, download and install a free file converter from the Microsoft Download Center. Next, update the service pack for your version of PowerPoint, choosing from Microsoft Office 2000 Service Pack 3, Microsoft Office XP Service Pack 3 and Microsoft Office 2003 Service Pack 1, all available at the Microsoft Download Center.
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- Microsoft Office: PowerPoint 2007
- Microsoft Office: PowerPoint 2010
- Microsoft Download Center: Microsoft Office Compatibility Pack for PowerPoint File Formats
- Microsoft Download Center: Office 2003 Service Pack 1
- Microsoft Download Center: Office XP Service Pack 3 (SP3)
- Microsoft Download Center: Office 2000 Update: Service Pack 3 (SP3)