File types in OS X

This Article is for those new to the Mac or for those who have questions about the different file types in OS X. The lists below aren’t complete and in many cases may require the user to install additional Apple software or third party tools.

File Extensions

The table below lists some of the commonly encountered file types. Note that in certain situations, like creating & extracting from zip files, the related application is not directly invoked.

Common extensions in OS X

Common extensions in OS X


The table below shows some of the popular third party file types that once can access on OS X. Note many of them may require users to install 3rd party applications to open/edit the files. Do note that the list below is not a complete list.

Popular file types

Popular file types



Showing File Extensions

Here are the steps to show file extensions.

1) Look at the Application running. Make sure the Finder Application is running by viewing the upper left hand corner of the screen.


2) Click on Finder


3) Click on Preferences

4) Click on the ‘Advanced’ Tab. Look at the selection for File Extensions.


5) Make sure the checkbox to show file extensions is selected.