Nuendo 8.2.1 UA Apollo Thunderbolt ERROR -38

I’m posting for the first time…

I’ve been running Nuendo / Cubase for about 5 years now.

I recently purchased a 2017, Retina 5k, 27" iMac and am running 8.2.1 on it.

My audio interface is a Universal Audio Apollo quad with a quad UAD-2 satellite daisy-chained to the imac with the apple thunderbolt to USB-C adapter.

I also have an early 2011 MBP with Nuendo 8.2.1 on it. Both Macs are running 10.13.6 .
The apollo is running UA console software 9.6.1 .

I started experiencing an apollo -38 error (on the new iMac (thunderbolt throughput error) shortly after setting up this system. ( Plug-ins would be disabled)

To test I created a test nuendo session with enough UA plugs to run the DSP to 95%.

This session exports fine time and time again on the old macbook pro.

It consistently fails on the new iMac.

Today I installed my assistant’s copy of Pro Tools 12 on the NEW iMac…ran a similar test session (95%) DSP and was able to print a mix time and time again…no problem!

My other observation: While exporting in Pro Tools I was able to type email and mouse around no problem.
During my testing with Nuendo the same behavior results in the keyboard freezing while typing and the mouse jetting off the screen…

Since the old MBP is functioning correctly with Nuendo / UA thunderbolt and Pro Tools 12 is functioning correctly on the NEW iMac with UA over Thunderbolt, I can only conclude that there is a software issue with 8.2.1 on the new iMac. Who’s with me?! Please help!!!

iMac Specs:
Retina 5K, 27 inch, 2017
4.2 GHz intel Core i7
40GB 2400 MHz DDR4 Ram
Radeon Pro 580 8GB

UA apollo:
Silverface quad with thunderbolt option card
UAD-2 Quad Satellite

Mac thunderbolt to USB-C adaptor

CalDigit hub with dual 1080 HDMI monitors

Black Magic UltraStudio Mini Monitor (thunderbolt to HDMI for Nuendo Video Out) on the thunderbolt adaptor daisy chain.

Absolutely!!! the same issue. I am using the IMACPro with Nuendo 8.2.1. Exporting mixes gives me intermittent -38 error with the UAD-2 QUAD Satellite module in which plugins are disabled. The only short term fix I have found is exporting the mix in “real time”. I am in contact with UAD about this issue. They directed me to the this posting in the forum today.