Show File Name Extensions in Mac OS X
File extensions (like .jpg, .txt, .pdf, etc) make it easy to see what a specific file type format is, but as many Mac users notice, those file extensions are hidden by default in Mac OS X. While hiding the format suffix makes for a cleaner user experience and is fine for many users, it can be frustrating if you’d rather know instantly what file format type a file is just by looking at the name, and for many power users it’s one of the first things changed when setting up a Mac.
As we’ll demonstrate, OS X offers two choices for displaying file format extensions after file names: You can either set all extensions to be displayed for every file in Finder through a universal setting, or you can set extensions to be shown on a per file basis with the help of the Get Info command. For either choice, the file format type will be shown as part of the file name, changing something like “File” to display as “File.txt”.
How to Show or Hide All File Extensions on Mac
All versions of OS X allow for showing file name extensions the same way in Finder, here’s what you’ll need to do:
- From the Mac OS X Desktop, pull down the “Finder” menu and choose “Preferences” (this is labeled as ‘Finder Preferences’ in some versions of OS X)
- Click on the “Advanced” tab (gear icon)
- Check the box next to “Show all filename extensions”
The setting to reveal filename extensions should be immediate, though some versions of OS X have a slight delay for revealing the extensions on visible files. This can be expedited by simply toggling the setting again to immediately display them (this is shown in the video below).
The setting is in all versions of OS X, it does not matter what is running on the Mac.
Changes are immediate and you’ll find the extensions visible instantly across the Finder for all files and file format types, the screen shot below demonstrates this:
The video below demonstrates showing file name extensions on all files and in all folders of a Mac:
To hide the filename extensions you simply need to keep the setting toggled off.
You can also selectively show and hide filename extensions on a per file basis.
Selectively Show or Hide Filename Format Extensions
If you’d rather not see them all, or if you want to hide some and show others, you can also show (or hide) file extensions on a per file basis.
- Select a file and hit Command+i to bring up the “Get Info” window
- Click the arrow alongside “Name & Extension:” to expand the options, and check or uncheck “Hide extension”
For many users, not seeing filename extensions is probably fine, but I often set custom file associations, and knowing the extension will let you know what app is going to open with each file without looking at the “Open With” menu to be certain.