Some additional data after some troubleshooting.
🔹 Key Observations
- TAB fails only on your built-in keyboard when logged in as your primary user.
- Works fine with external USB keyboards.
- Works fine with the same built-in keyboard if you log into a second user account.
- Problem persists in Safe Mode on your primary user account.
- Safe Mode disables most third-party extensions, caches, and background agents.
- Since the problem persists here, that rules out most third-party software and startup items.
- Problem is per-user, not system-wide.
- The second admin account works perfectly.
- This is a classic per-user corruption pattern.
- Numbered/bulleted list TAB behavior is affected in multiple apps.
- Not limited to Apple apps (Cocoa text system) — includes Microsoft Teams (Electron/Chromium).
- So it’s likely a user-specific keyboard input mapping problem that affects all apps.
- External keyboard bypasses the issue.
- Confirms that macOS is correctly interpreting TAB events globally for another device.
- Suggests the built-in keyboard input is being modified per-user, not broken at the hardware level.
🔹 What We’ve Already Tried
StepResultRemoved ~/Library/KeyBindings/DefaultKeyBinding.dict - No effect
Removed user Keyboard Services / HIToolbox / Input Methods / Keyboard caches - No effect
Reset TCC / Accessibility / keyboard services - Partial success; TAB still broken
Reboot in Safe Mode - Issue persists
External USB keyboard - TAB works
Creating a new user account - TAB works
Reinstalling OS - No effect (per-user)