In case it’s useful for anyone, this is the 2009 version of Xynthi I mentioned a few posts back that I run here under High Sierra with no issues. I asked Bhob if it was OK to share, he’s fine with it so here it is:
I run it principally on a desktop machine, it displays rather oddly on a Macbook but other than that seems OK there too.
Mac Mini w/ High Sierra 10.13.6
MOTU Ultralite Mk3 Hybrid set to 48kHz
I can’t shed any light on why it works and nor could Bhob, it doesn’t open here if I have any kind of aggregate device set up in my sound settings but straight to the MOTU is fine. Hope it helps.