The value
HKCU\Control Panel\Keyboard → InitialKeyboardIndicators. Version history explains the strange values: 2 = NumLock on at sign-in, 0 = off; Windows 8+ introduced 2147483648|x forms that preserve the value across Fast Startup cycles, so stock machines commonly show 2147483650.
The rules that actually apply
- Evaluate per account after a fresh session; Fast Startup can restore the prior toggle into the session for you, which makes manual tests misleading unless you fully sign out.
- Per-user because it's per preference: the value is written by Setup on first profile creation and again when some keyboards' drivers apply their defaults.
- The on-screen keyboard's NumLock toggle at the logon screen writes through the same value — it is the manual alternative to editing.
One value, two real states, eleven-digit noise value explained. Where tools prove their worth is exactly this: replacing forum folklore with the documented state machine.
ProofTune ProjectEngineering notes — every claim here names the bytes a real tool touches. Verify first, install second.