Make Windows 11 Show File Extensions Everywhere

By Game Osborne · September 15, 2026 · Windows · Windows 11, File Explorer, file extensions

Reveal complete filenames in File Explorer and administrator windows so disguised downloads and attachments are easier to spot.

What file extensions reveal

A file extension is the short ending after the final dot in a filename. Examples include .pdf for a PDF document, .jpg for a picture, and .exe for a program.

Windows often hides these endings. That makes filenames look tidier, but it also hides useful information. A dangerous attachment called Invoice.pdf.exe might appear as Invoice.pdf when extensions are hidden. The familiar-looking name does not make it a PDF. Its real .exe ending means it is a program.

Showing extensions will not automatically decide whether a file is safe. It does, however, give you an important clue before you open it.

Turn on file extensions in File Explorer

These instructions assume you are using Windows 11. This is the quickest method, and it changes the setting for your Windows account.

1. Open File Explorer by clicking the yellow folder icon on the taskbar.
2. Click View on the toolbar at the top of the File Explorer window.
3. Point to Show in the menu that appears.
4. Click File name extensions so a check mark appears beside it.

Check that it worked

The change should appear immediately. Look at a few files you recognize. A picture may now end in .jpg or .png, while a document may end in .docx or .pdf.

Windows may warn you if you accidentally try to rename an extension. That warning is helpful. Choose No or Cancel unless you deliberately intend to change the file type.

1. Open a folder containing a document or picture.
2. Confirm that the filename now includes an ending such as .pdf, .jpg, or .docx.

Make administrator windows follow the setting

There is no separate switch just for administrator windows. Standard File Explorer and file-selection windows normally use the extension setting belonging to the Windows account that opened them.

An administrator window is an app opened with elevated permission, usually after Windows displays a User Account Control confirmation. If that app was already open when you changed the setting, it may need to be restarted before its Open or Save window catches up.

1. Close the administrator app whose file window still hides extensions.
2. Open that administrator app again.
3. Open its standard Open or Save window.
4. Check whether the displayed filenames now include their extensions.

Use a command if the setting will not stick

If File Explorer keeps hiding extensions, you can set the same preference with one Command Prompt instruction. Command Prompt is a text-based Windows tool. It may look technical, but you are only pasting one specific command.

This command changes the HideFileExt setting to 0, which tells Windows not to hide known file extensions. Run it while signed in to the account whose windows you want to fix.

1. Open the Start menu.
2. Type Command Prompt.
3. Click Run as administrator beside the Command Prompt result.
4. Click Yes if User Account Control asks for permission.
5. Type reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced" /v HideFileExt /t REG_DWORD /d 0 /f into the Command Prompt window.
6. Press Enter.
7. Close the Command Prompt window after the operation completes successfully.
8. Restart File Explorer and any administrator apps that were already open.

If you use a different administrator account

The setting is stored separately for each Windows user. If you enter the username and password of a different administrator account when opening an app, that app may use the other account's preference.

In that situation, sign in to the administrator account and repeat the File Explorer steps there. Do not make random changes in the Windows Registry, which is the settings database adjusted by the command above.

Some programs use their own custom file browser instead of the standard Windows Open or Save window. Those programs may have a separate option, so Windows cannot guarantee extensions inside every third-party interface.

Bottom line

Turn on View > Show > File name extensions, then restart any administrator apps that were already running. Once you can see the real ending of every filename, suspicious double extensions become much easier to catch before you open them.