I managed to get a new "Cable Matters" Brand cable from Amazon overnight and plugged it in, booted the Mac and the no audio issue appeared straight away. I've also purchased a Lindy cable but it will take few days to arrive and I'll test with that as well.

The next step I think will be to try a different USB bus on the computer.

I thought the UFX lll with all FX suited needs the access for FX record channels.

@Paulnajar : Yes, that was older MacOs where we could manually add applications to the microphone access.
Apple changed that and now a popup appears as soon a program with audio input channels tries to run.

What else can block the communication of the driver to the unit ?

USB-port, USB-cable, CC-mode

Is the unit set to USB-2 and CC-mode ?

the driver per se is not blocked, the Settings dialog does work.
But the audio from or to the unit is not open. (Typical symptom of mic access denied)

Your logic seems good and yet…
UFX3 is in full bandwidth usb3 mode and no cc. I need it that way has I use the MADI port a lot. The computer port it’s connect is a usb3 3.1 port.

Does this ever happen if you switch on the UFX after bootup? Or does that sequence make a difference? Have you tried another cable?

I haven’t tried this power on after computer boot but I will.

Regarding your suggestion to change cable, I went looking for a new USB3 - USBC cable thinking I had one but best I could find was USB3 - USBA so I added one of my A to C adapters and in a few hours of just Atmos listening there were a few dropouts. Worse performance than the previous cable which pretty well never had dropouts under the same conditions.

So if I were to buy a new cable - USBc to USB3 is there one that comes highly recommended above others?

paulnajar wrote:

waedi wrote:

Totalmix is listed and enabled in the Microphone access in MacOS system preferences / Security & Privacy ?

Well this could be a clue. I do a lot of live multichannel audio recording with the UFX3 amongst other things so microphone access works in some shape or form and my guess was it definitely must be listed in Microphone within privacy/ Security but it's not! Digicheck NG is but not Totalmix and I could see no way to add access.

TM FX does not require mic access unless you use a Babyface (FX record channels). I explained that to waedi already before.

Thanks for clarification MC.

USB-port, USB-cable, CC-mode

Is the unit set to USB-2 and CC-mode ?

It cannot be CC-Mode or acces denied. Because the issue happens occasionly. Otherwise it would be continuesly not working.
USB-Port or cable is more likely. Because after a reset of the USB port (sample rate change) it works again.

@Paulnajar : Yes, that was older MacOs where we could manually add applications to the microphone access.
Apple changed that and now a popup appears as soon a program with audio input channels tries to run.

What else can block the communication of the driver to the unit ?

USB-port, USB-cable, CC-mode

Is the unit set to USB-2 and CC-mode ?

the driver per se is not blocked, the Settings dialog does work.
But the audio from or to the unit is not open. (Typical symptom of mic access denied)

waedi wrote:

Totalmix is listed and enabled in the Microphone access in MacOS system preferences / Security & Privacy ?

Well this could be a clue. I do a lot of live multichannel audio recording with the UFX3 amongst other things so microphone access works in some shape or form and my guess was it definitely must be listed in Microphone within privacy/ Security but it's not! Digicheck NG is but not Totalmix and I could see no way to add access.

TM FX does not require mic access unless you use a Babyface (FX record channels). I explained that to waedi already before.

paulnajar wrote:

Waedi, sample rate switching was done in RME settings.

Totalmix is listed and enabled in the Microphone access in MacOS system preferences / Security & Privacy ?

Well this could be a clue. I do a lot of live multichannel audio recording with the UFX3 amongst other things so microphone access works in some shape or form and my guess was it definitely must be listed in Microphone within privacy/ Security but it's not! Digicheck NG is but not Totalmix and I could see no way to add access.

The web suggested unlocking the section to add a new app but I can't see a way to do that. I think the Gemini AI was referencing an earlier MacOS version. I'm on Tahoe 26.7.1

I also started to wonder whether it is Toitalmix that requires microphone access or the RME KEXT driver extension. I looked in extensions in System Preferences and there is no mention of it there but when I gather System Information/ Extensions the RMEFirefaceUSB KEXT extension is listed.

Any thoughts Guys?

Kind regards

Waedi, sample rate switching was done in RME settings.

Conclusion : The driver was up and working somehow or partially.
I would also try the DK and MacOS 27 (with a backup ready)

Totalmix is listed and enabled in the Microphone access in MacOS system preferences / Security & Privacy ?

It only happens occasionally but strangely after the issue appeard yesterday for the first time in a month or more this morning the cold boot up showed the issue again.

I will get around to trying a different USB port and cable soon but I don't hold much hope in this improving things. The computer is a Mac Studio and the UFX3 has it's own dedicated USB 3 port with no other device attached on that port and the factory USB 3 cable is used and the UFX3 performed very well for the first year or more before the problem began. My instinct is it's some OS level issue that appeared after an update. Maybe it's time I went and gave the driver kit driver another go. I know I'm going to have to eventually.

The issue is not killing me and once the fix has been applied the whole system is very stable but I do appreciate the thoughts guys.

Kind regards
Paul Najar