the included migration software) and so called "Pro" products
So you used migration it seems......
For now I conclude with the work around suggested in several places: create a new administrator account and go from there. It is the only thing that solved my problems with LPX.
An issue that is fixed by using a different User Account almost always relates to a permissions problem... typically caused by the User moving data from one account or computer to another via Migration etc...
As always, I strongly suggest that you don't use Migration to move Logic and it's content to a new Mac... but manually reinstall from scratch to prevent such issues...
The fact that using a new Account fixed things also may suggest you will have other permissions related issues in the future unfortunately...
You may wish to start again from scratch, reformat your system drive... and install OS X again.. using the recovery partition..manually Install all Apps and content again, and manually move any/all personal data/docs etc... to prevent the possibility of other permissions related problems occurring.
Doing this now will likely save you a lot of time and hassle, later...