Show Filename Extensions in Mac OS X
File extensions (.jpg, .txt, .pdf, etc) are hidden by default in Mac OS X, this makes for a cleaner user experience and is fine for most users, but it drives me nuts and it’s one of the first things I change when setting up a Mac. You can either set all extensions to be displayed 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, here’s how to do both:
Show or Hide All File Extensions
- From the Mac OS X Desktop, pull down the “Finder” menu and choose “Finder Preferences”
- Click on the “Advanced” tab (gear icon)
- Check the box next to “Show all filename extensions”
Changes are immediate and you’ll find the extensions visible instantly across the Finder:
Selectively Show or Hide Filename 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.
Showing file extensions is useful for files with different formats saved with the same name, for example, I may have an “order peanuts” text file, and an “order peanuts” JPG file. Since I exclusively use column view, it is hard to distinguish the file format based on the small icons. To keep the display names short I prefer to set show extension only for individual files.
This is one of those ‘must do’ changes as soon as you boot a new Mac. That and dragging half the garbage out of the Dock.
The Finder setting to hide extensions is hit and miss – it works for some files but not others. It definitely doesn’t work with MS Office 2008/2011 files – their extensions show all the time. Adobe PDFs sometimes show, sometimes not. Files created by Apple applications seem to be the most consistent, so I suspect its a third-party adherence to Apple software and/or GUI guidelines that determine if extensions show or not..
having said that, I am at the other end of the spectrum – I NEVER want to see extensions, and wish there was some universal Terminal command to banish them forever.
“File extensions (.jpg, .txt, .pdf, etc) are hidden by default in Mac OS X, this makes for a cleaner user experience and is fine for most users, but it drives me nuts and it’s one of the first things I change when setting up a Mac.”
Exactly. Hidden extensions are so annoying. It’s one of the first settings I change.
In this connected age, showing file extensions is a must. There ARE files that could infect even a Mac, and extensions are one quick way to know what a file is without clicking on it.
[...] you have file extensions shown in the OS X Finder, attempting to change a file extension causes a warning dialog with a confirmation [...]
Thanks for posting this. Changing this setting is just as much a must in Mac as it is in Windows. Showing extensions is definitely a must for professionals. Again, thanks!
[...] sure to have file extensions visible on all files in OS X, that way the extension change will be visible in the Finder in addition to [...]
[...] of not knowing what’s a .jpg, .png, .gif, or whatever else just by looking at the extension? Show those file extensions and you can easily identify file formats just by looking at the [...]