.MMC File Extension
File TypeMicrosoft Media Catalog
File format categories include Binary, Text, XML, and Zip. The format of this file type has not been determined.
What is an MMC file?
Contains a collection of images (such as a clipart gallery) or other media in an organized format; typically saved in the \Application Data\Microsoft\Media Catalog directory.
An example of an MMC file is the "Artgal50.mmc" catalog file, which contains images, keywords, and thumbnail previews used by Clip Gallery.