The extension SLDX identifies a file containing slides in the Office Open XML format of the Microsoft PowerPoint presentation software as of version 2007 (Mac 2008). These files can contain text, tables, images, audio and video data. The slides can be inserted into a presentation by inserting an object. Files containing macros are marked with the extension sldm.
SLDX is an XML-based file format (Office Open XML) that is unreadable with earlier versions of PowerPoint. For the Office versions 2000, 2003 and XP, this functionality can be remedied with the help of the Microsoft Office Compatibility Pack, whereby the result of an imported SLDX file does not always have to correspond to 100% of the original.
An SLDX file consists of several XML files, which are automatically summarized as archives when saved with the ZIP algorithm. This saves space compared to the old format. Other benefits include better data integrity and easier data recovery in case of data loss.