I like to use my MacBook with a USB mouse most of the time, and keep "Ignore built-in trackpad when mouse or wireless trackpad is present" option checked to avoid accidentally moving the cursor while typing. However, occasionally it's useful to switch it back on for certain tasks, and I'd like to be able to do this with a keyboard shortcut.
I've tried recording the process of switching it on/off with Automator, but when I copy the resulting script and run it, it gets as far as the Accessibility settings and then gives me a syntax error saying 'Can not click checkbox 3 of window "Accessibility" of application process "System Preferences"'.
I've also tried setting "USBMouseStopsTrackpad" in defaults to 0 and 1 in the terminal, but it doesn't seem to do anything. I can see this changing to 0 or 1 when I check/uncheck the box, so I'm fairly certain I've got the right option, but nothing happens when I change it.
Apologies if this is really obvious and I'm just not seeing it! I'm still not too familiar with this machine. I'm aware of this question:
but I don't think it's a duplicate as I'm trying to do something slightly different.