Remove Gallery from the File Explorer sidebar — via Mauro Huculak, Pureinfotech

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: Remove Gallery from the File Explorer sidebar

[HKEY_CURRENT_USER\Software\Classes\CLSID\{e88865ea-0e1c-4e20-9aa6-edcd0212c87c}]
"System.IsPinnedToNamespaceTree"=dword:00000000

Undo

Windows Registry Editor Version 5.00

; Oddbyte.Me: undo Remove Gallery from the File Explorer sidebar

[-HKEY_CURRENT_USER\Software\Classes\CLSID\{e88865ea-0e1c-4e20-9aa6-edcd0212c87c}]

Same thing from a command prompt

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

reg add "HKCU\Software\Classes\CLSID\{e88865ea-0e1c-4e20-9aa6-edcd0212c87c}" /v "System.IsPinnedToNamespaceTree" /t REG_DWORD /d 0 /f

Undo:

reg delete "HKCU\Software\Classes\CLSID\{e88865ea-0e1c-4e20-9aa6-edcd0212c87c}" /f

The key doesn't exist under HKCU by default; you create it, and undo deletes it. Only your account is affected.