Show hidden files and protected operating system files — via How-To Geek

The easy way

1. Hidden files only, the easy way: File Explorer → View → Show → Hidden items.
2. For protected system files: File Explorer → … → Options → View → untick Hide protected operating system files (Recommended).

Registry change

Double-click a .reg file and confirm to merge it. Right-click → Edit first if you want to read it, which is always a good idea with any .reg file from the internet.

Apply

Windows Registry Editor Version 5.00

; Oddbyte.Me: Show hidden files and protected operating system files

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced]
"Hidden"=dword:00000001
"ShowSuperHidden"=dword:00000001

Undo

Windows Registry Editor Version 5.00

; Oddbyte.Me: undo Show hidden files and protected operating system files

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced]
"Hidden"=dword:00000002
"ShowSuperHidden"=dword:00000000

Same thing from a command prompt

Run in a normal (non-admin) Command Prompt or Terminal.

reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced" /v "Hidden" /t REG_DWORD /d 1 /f
reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced" /v "ShowSuperHidden" /t REG_DWORD /d 1 /f

Undo:

reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced" /v "Hidden" /t REG_DWORD /d 2 /f
reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced" /v "ShowSuperHidden" /t REG_DWORD /d 0 /f

Hidden: 1 shows hidden items, 2 hides them. ShowSuperHidden: 1 shows protected OS files, 0 hides them (recommended). Apply only the first value if you just want hidden files.