Where did my right arrow key go?

This behavior points to a Windows keyboard setting rather than a Word setting.

Try these checks in order:

1. Check whether Mouse Keys is turned on. When enabled, the numeric keypad can be repurposed for navigation instead of normal key behavior.
   • Open Windows Settings.
   • Go to Ease of Access.
   • Select Mouse.
   • Make sure Mouse Keys is Off.
2. If Mouse Keys is already off, turn it On, then Off again, and restart Windows.
3. Run the built-in keyboard troubleshooter:
   • Open Command Prompt.
   • Run:

          msdt.exe -id KeyboardDiagnostic
     

   • Complete the troubleshooter and test the right arrow key again.
4. Test with Num Lock on and off after the restart.
   • If the dedicated right arrow key works only when Num Lock is off, but not when it is on, that still indicates a keyboard/input handling issue in Windows.
5. If the problem continues, test with another external keyboard if available. If another keyboard works correctly, the original keyboard is likely the cause.

Word itself uses the Right arrow key for navigation, but the issue described is occurring before Word shortcut behavior, so Windows keyboard settings are the first place to check.

• My number pad on my keyboard is making directional moves instead of typing numbers. - Microsoft Q&A
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• Keyboard shortcuts in Word