Mac101 – File Name Extensions

For years the Mac, by default, has not displayed the file name extension. The file name extension is the three characters at the end of your file name right after the period, like filename.pdf for instance. People just did not pay it any mind. But, not so these days.

Name Extensions

For some of us turning on file name extensions is totally not needed. They don’t use a lot of files and don’t have a need to know file extensions. However, I want to know and see the file extension information. Yes, many files have an icon for the app that opens them so they are identifiable, but not always, plus sometimes the icon is from an obscure program that you do not use much. So, I turn on the file extensions. If you wish to tun on file extension then do the following. Go into your Finder Preferences:


Once you are in the Preferences area then select the “Advanced” tab:


Check the box “Show all filename extensions” and then close the window. Your files and apps will now show a file name extension like this:


I really like seeing what type of file I am using at a glance. It just makes things easier and more efficient for me.


If you have decided you need to see your file extensions or not see them, then there is an easy way to turn them on or off.