How to Show Filename Extensions on Mac Running macOS Sierra

What’s a file extension and why it’s so important? Well, a file extension is shown at the end of a file and starts with a period which is followed by a few letters or words. As for instance, .png. A file extension shows both the file type and the particular app that can open it. Depending on your need, you can show or hide individual or entire filename extensions on your Mac.

By default, file extensions are hidden on Mac. I guess Apple does it just to ensure all the file names have the similar view. Even if extensions are hidden, files open with the proper apps. Read on to find out more…

How to Show or Hide Filename Extensions in macOS Sierra on Mac

You must know:

  • At the time of renaming a file or folder, make sure not to change its filename extension otherwise you won’t be able to open the file with the app which was used to create it
  • If you want to be warned before changing an extension, make sure to select “Show warning before changing an extension” which is included in Advanced pane ofFinder preferences
  • Just in case you wish to change a file’s format, you must use the app that was used to create the file

How to Hide or View Individual File Extension on Mac

Step #1. First off, you need to select the individual file which extension you want to show or hide.

Select File of Which You Want to View Extension

Step #2. Next, right click on it and then select Get Info or simply press Command-I.

Click on Get Info in File on Mac

Step #3. Next up, you have to click the triangle next to Name & Extension in order to expand the section.

Click on Triangle Shape in Get Info Window on Mac

Step #4. Finally, check the box next to Hide extension in order to hide the file extension. If it’s already hidden, uncheck the box in order to show the file extension.

Show Hide File Extension on Mac

How to Hide or Show All File Extensions in macOS Sierra on Mac

  • When the “Show all filename extensions,” option is selected, the extensions will show up for all files—irrespective of whether the Hidden extension has been selected for any file or not
  • However, when you deselect “Show all filename extensions,” then file extensions will be shown or hidden in accordance with their individual “Hide extension” settings

Step #1. Open Finder on my Mac.

Step #2. Next, click on Finder at the top left corner.

Step #3. Now, you need to select Preferences.

Click on Preferences in Finder on Mac

Step #4. Next up, click on Advanced.

Click on Advanced Tab in Finder Preferences on Mac

Step #5. Finally, check the box next to Show all file extensions in order to make the files show up the extensions.

Click on Show all filename extensions on Mac

Just in case you want to hide all the file extensions, uncheck the box.

That’s it!

The Bottom Line

I like to make files show their extensions as it brings more convenience into the play. It would have been better had extensions shown up by default. What’s your take on it?

You might want to have a quick glance at best Mac Dock shortcuts, how to hide or unhide images in Photos app on Mac, and how to speed up macOS Sierra.

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The founder of iGeeksBlog, Dhvanesh, is an Apple aficionado, who cannot stand even a slight innuendo about Apple products. He dons the cap of editor-in-chief to make sure that articles match the quality standard before they are published.