After downloading GPO5 recently I bought Logic Pro X and now realise I should have saved GPO5 to my external drive (ie on a different drive from Logic Pro X).

To move the files in the way suggested in the help advice I have to edit the .plist file but my Mac won't let me. I understand I could try creating a Root account on the Mac where I would have the relevant permissions but I'm very wary of doing this in case I mess it up!

I thought I could just uninstall GPO5 and then reinstall into the external drive. I've just downloaded it again but when I select my external drive I get an error message saying that GPO5 "...can't be installed on this disk. You can only install this software on the disk that's running MacOS."

Does anyone have any advice about how to proceed?

My Set-Up:

2013 iMac, OS X Sierra 10.12.2, Finale 25, Logic Pro X

Any help much appreciated. Thanks and happy new year.