Nuendo 13 won't see previous audio driver

Well this is a real mood killer.
N13 Trial. Running on M2 in the studio and MacBook Pro elsewhere. I’ve been using it on the MacBook for a couple of days with no issues, Metric Halo ULN-2 Legacy firewire running on Monterey with Thunderbolt adapter.
This morning I came back to work on a project and Nuendo refuses to see the MH driver, only built in audio.
Re-start, Macbook and ULN, restart Nuendo, every combination of shutting down and re-booting, re-starting, no luck.
Re-installed Nuendo. No luck.
MacBook sees the Audio device, Cubase 12, Cubase 14, Studio One, VST Live 2 ALL see the audio device.
Nuendo does not.
I hope there is a solution to this incredibly frustrating problem. Is there a preferences folder I should trash? Why does Cubase see the driver and Nuendo not? I thought they used the same audio engine.
Thanks for any advice.