Sugar-bytes Guitarist shows up Stand Alone but missing from Logic Audio Units Manager



I've been advised to move down a Mac OS 10.10.5 from Mac OS 10.11.6. I did tjhis because I was told that there are compatibility issues. Now that I've 'Downgraded' to a lower Mac OS, I have to re-load all my AU's.
The only one giving me trouble is sugar-bytes Guitarist. I have the Stand Alone version appears 'when called' BUT NO SOUND and it doesn't even show up in Logic's Audio Imports Manager.

May I ask some advse to learn how to FULLY retrieve? Thank you for Reading