…On my test run, it gave me the "not from a trusted developper" message.….
Automator(and 'Mail' in this script) is an Apple.app, delivered with any installation of macOS.
So, Apple doesn't trust Apple… ? Consider a from-the-ground-update. Or, perhaps, do you run Mojave_beta?
I did this account just for thank you.
By the way, I can't do that script with any compressor presets, because there is no field "open with" then I can't select that script on fcpx settings, only the built in "master file" fcpx preset has that option, anyway its helpful. thanks again!