How to display file extensions in Mac and Windows
How to list files in Details view in Windows

Instructions For both Windows 7, 10, and Mac

Table of Contents

What are file extensions?

Further information: Lists of file extensions

There are hundreds, probably thousands, of file extensions. The following sites provide more information about them.

Setting a Mac to display file extensions

If file extensions do not appear n the Finder you will now set your Mac to make file extensions visible. Please do the following:

  1. First, open the Finder's Preferences.
    • If you don't know how to select the Finder, hold down the Apple (Command) key ( ⌘ ) on your keyboard and, as you hold it down, tap on the Tab key again and again until you select the blue smiley Finder icon: Mac Finder Icon - then stop tapping the Tab key and remove your finger from the ⌘ key.
    • Now you are set to the Finder. To be certain of this, the word Finder ought to be visible to the immediate right of the  icon in the upper left of the Mac screen. If not, try the procedure in the bullet point item directly above.
  2. Next, from the Finder menu, select Preferences... see item 1 in the illustration below.
  3. In the Finder Preferences dialog box ( 2 ).
  4. Enable Show all filename extensions ( 3 ).
Setting Macs to show file extensions

Setting Windows to display file extensions

Windows XP, Vista, 7, 8, and 10 - Brief instructions by Adobe

Windows 7 - More detailed instructions by Dan

  1. Right click on Window's Start button.
  2. Select Explore or Open Windows Explorer or File Explorer (depending on your Windows version).
  3. Windows Explorer (or File Explorer) will open.
  4. On the left side of the menu bar click on the Organize button and select Folder and search options from the menu.

  5. In the dialog box that opens, click the View tab.
  6. In the Files and Folders section DE-select (disable) Hide extensions for known file types. *
  7. Close the dialog.

* The words "known file types" suggests that there are file extensions that are unknown to anyone, which is probably not true.

Setting Windows to display files and folders in "details" view

You will now set Windows to provide many types of information about files and folders:

Set your student folder

Set your student folder to apply the file display settings that you will be making below to all files and folders within your student folder:

  1. Open Windows Explorer (or, File Explorer on Windows 10).
  2. Right click on your student folder
  3. Select Properties
  4. Click on Customize tab.
  5. Beneath Optimize this folder for: select Documents
  6. Enable (check) the checkbox Also apply this template to all sub-folders
  7. Click Apply
  8. Click OK


  1. If it is not already opened, please open Windows Explorer or File Explorer (this depends on the version of Windows).
  2. Right click on the Start button in the lower left corner.
  3. Select Explore or Open Windows Explorer or File Explorer, again, the choice depends on the version of Windows that you are using.
  4. To set your files to be viewed in Details view:
    1. For File Explorer (Windows 10):
      1. Click on the View menu to open the ribbon for it.
      2. In the Layout section select Details
    2. For Windows Explorer (Windows 7):
      1. On the upper right side of the menu bar there is a button that lets you set the type of view of the folders and files.
        • To check what the button does, hover over the button, and a tool tip will appear: Change your view
      2. Click on the button.
      3. The choices are either icons, names, or various combinations of the two (see next illustration).
    3. Select Details. I always recommend using Details view because it provides the most information.

Sub-folders and files ought to display in Details view automatically within your student folder. If the view is other than Details view:

  1. Follow steps 4-5 in the Setting Windows to display file extensions section above.
  2. In the top part of the dialog, in the Folder views section, select Apply to Folders, then OK it.

Comparison of Large Icons and Details views

Icons view

Details view