In this instance, I’m using a Windows 10 laptop with a precision touchpad.
Follow these steps to automatically disable the touchpad of your Windows 10 laptop when an external mouse is connected:
Uncheck the option “Leave touchpad on when a mouse is connected.”
Note: Select the option above to switch to the default setting (which is enabled).
Launch Registry Editor. I suggest backing up the Registry before proceeding.
Go to HKEY_CURRENT_USER > Software > Microsoft > Windows > CurrentVersion > PrecisionTouchPad.
In the right pane, you can see LeaveOnWithMouse DWORD. Double-click it.
Provide ffffffff (to enable) or 0 (to disable) in the Value data field.
Hit the OK button.
Restart your PC.
I hope this guide, “How to Disable Touchpad When a Mouse is Connected,” is helpful to you.
Thanks for reading.