Stop the Sticky Keys pop-up when you press Shift five times — via Microsoft Learn

The easy way

1. The easy way: Settings → Accessibility → Keyboard → Sticky keys → turn off Keyboard shortcut for Sticky keys.

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: Stop the Sticky Keys pop-up when you press Shift five times

[HKEY_CURRENT_USER\Control Panel\Accessibility\StickyKeys]
"Flags"="506"

Undo

Windows Registry Editor Version 5.00

; Oddbyte.Me: undo Stop the Sticky Keys pop-up when you press Shift five times

[HKEY_CURRENT_USER\Control Panel\Accessibility\StickyKeys]
"Flags"="510"

Same thing from a command prompt

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

reg add "HKCU\Control Panel\Accessibility\StickyKeys" /v "Flags" /t REG_SZ /d "506" /f

Undo:

reg add "HKCU\Control Panel\Accessibility\StickyKeys" /v "Flags" /t REG_SZ /d "510" /f

The Settings toggle is the recommended way and applies immediately; the registry value is read at sign-in. The 510 (default) and 506 (shortcut off) values come from a 2007 Microsoft blog post, so check your current Flags value first and note it down: if it isn't 510, use the Settings toggle instead.