I downloaded SU 17 this morning on my MacBook Pro running OS Sierra, as I was having problems since the OS upgrade. I was running SU pro 15 on El Capitan before.
Initially I had lots of bug splats when trying to edit text, and couldn’t open some of my existing Layout files.
What I did notice though, was that when I was trying to copy my own templates from SU 15 to SU 17, there was no Layout folder in the SU17 Application support folder, so nowhere to put the templates folder.
I copied the whole folder from SU 15 and since then all seems to be running better and no more bug splats. I don’t know if the Layout templates are intentionally stored elsewhere or if this was a mistake/omission?