Quick fix: Open File Explorer, click View in the toolbar → Show → File name extensions. Tick it. Every file now shows its extension (.txt, .docx, .exe). Also tick Hidden items if you need to see hidden files.

You open File Explorer and see report without the .docx ending, image1 without .jpg. Windows 11 hides file extensions by default — a holdover from Windows’ original goal of making the interface less intimidating. The cost: phishing emails with attachments named “invoice.pdf.exe” show as “invoice.pdf” in Explorer, and you have to guess what extension a file has. Showing extensions takes one click.

Symptom: File names in File Explorer don’t show their extensions (.txt, .docx, .exe).
Affects: Windows 11 (and Windows 10) by default.
Fix time: ~1 minute.

What causes this

Windows hides extensions for “known file types” — extensions registered with the OS’s file association list. Unknown extensions still show. This is a usability decision (less visual clutter for typical users) and a security risk (extensions are how malware files disguise themselves). The setting is a single boolean — Windows just doesn’t expose it prominently.

Method 1: Toggle via File Explorer’s View menu

The standard approach.

Open File Explorer (Win + E).
Click View in the toolbar (or the three-dot menu in older versions).
Hover Show for the submenu.
Tick File name extensions.
Every file now displays its extension. The change is system-wide and immediate.
While in the Show submenu, also tick Hidden items if you want to see hidden files and folders.

The setting persists across reboots.

Method 2: Use Folder Options for more control

Use when you also want to see protected operating system files, or to apply the setting to all users.

Open File Explorer. Click the three-dot menu in the toolbar → Options.
Switch to the View tab.
Untick Hide extensions for known file types.
Optionally untick Hide protected operating system files (Recommended) — this shows files like pagefile.sys and hiberfil.sys in the C: root. Re-tick after you’re done; visible protected files are a deletion risk.
Click Apply to Folders to apply the settings to all folder views. Click Apply → OK.

This is the legacy Folder Options dialog. Same setting as Method 1 but with additional options.

Method 3: Set globally via registry for all users

Use for fleet deployment or to make the setting persistent across user profiles.

Press Win + R, type regedit, press Enter.
Navigate to HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced.
Find HideFileExt DWORD. Set to 0 (show extensions) or 1 (hide).
For machine-wide: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced. Same DWORD name.
Sign out and back in for changes to apply universally.

Via PowerShell for automation:

Set-ItemProperty -Path "HKCU:\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced" -Name HideFileExt -Value 0

Restart Explorer to apply immediately: Stop-Process -Name explorer -Force; Start-Process explorer.

This is the right approach for IT deployment or scripts.

How to verify the fix worked

Open File Explorer. Files show their extensions (e.g., report.docx, image.jpg).
Right-click any file → Properties. The Type of file matches what you see in Explorer.
Run (Get-ItemProperty -Path "HKCU:\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced").HideFileExt in PowerShell. Returns 0.

If none of these work

If extensions still don’t show after toggling, three causes apply. Group Policy override: corporate-managed PCs may enforce hidden extensions. Run gpresult /h C:\gpresult.html and search for related policies. Cached Explorer state: in rare cases, Explorer caches the old setting until restart. Restart Explorer: Task Manager → right-click Windows Explorer → Restart. Per-folder view override: a specific folder may have been set to not show extensions via Folder Options → Reset Folders. After Method 1 or 2, click Apply to Folders to push the setting to every folder.

Bottom line: Hidden file extensions are a usability default but a security risk — one click in View → Show enables them, and the change is immediate and persistent.