Please post your specs.
Try a different USB port.
If the issue persists, please contact Support.
Thanks!

Bbd wrotePlease post your specs.
Try a different USB port.
If the issue persists, please contact Support.
Thanks!

I've tried different USB ports, front and back panel.
Asus x570 tuf gaming plus mobo
AMD Ryzen 5 3600
Corsair 750 watt PSU
EVGA GTX 970 GPU
4x8GB G.Skill Ripjaws 3200mhz CL16 RAM
Windows 10 home 64 bit
Fractal Design R5 case iirc.
The build is less than 2 years old.

So far support have just requested msinfo file, no advice.

Can you uninstall UC and download a fresh version?
Unplug the unit while you do that.
It may need to be replaced.
Support should be able to help. Send them whatever they need.

Bbd wroteCan you uninstall UC and download a fresh version?
Unplug the unit while you do that.
It may need to be replaced.
Support should be able to help. Send them whatever they need.

Thanks, I will try that now

I am hoping the unit doesn't need to replaced as it's been a journey so far to get this far.. I was advised that a Focusrite Scarlett 2i2 gen 3 would do the job I required (linked channels 1 & 2 gain, via 'control' software) but it isn't able to do that, so I took it back and have swapped for the io24 Revelator. I live quite far from the shop so it took all day yesterday to get to and from the shop and then test the unit.

But hopefully I can get it to work, or worst case the replacement will work.

What is the standard warranty for the io24 Revelator?

edit: A surprising update - after uninstalling the control software with the io24 removed, and
then reinstalling it with the io24 not connected, the io24 correctly loaded up (even prior to Windows 10 booting). Universal Control is correctly showing v1.21 firmware as well as the LED screen. Thanks for the help!! It seems like the Universal Control software was having some issues.

I forgot to mention I am installing this on my C:\ drive to default location, the drive is an NVME SSD, Samsung 970 Evo Plus 500GB.

edit 2:
I'm getting more weird errors.

Firstly, I linked channel 1 & 2 as that was the reason I bought the io24 over another interface, the option to link a left and right stereo pair's inputs. It showed 'channel 2' only on the mixer. I noticed however there was signal being shown - blue lights halfway down the channel strip LED metering. This confused me.
I tried lowering and raising the 'channel 2' (linked) fader in software, then I found I couldn't get it to sit at 0dB again, it was impossible to get it precisely on 0. I got -0.77dB or something like that as close as I could.

I think click 'unlink' or something similar in the bottom left corner, and the 1, 2, arrow and presets buttons started flashing, then the blue encoder knob starting flashing, the devices disappeared from Windows 'sounds' settings and universal control once again is telling me to 'update firmware new version 1.21'.

Something very wrong here.

Each time I reinstall Universal Control I am only installing the Revelator USB driver, not the other drivers.

Repeating this process a second time, uninstalling and reinstalling Universal Control and rebooting, brings the same issue.

A third attempt:
I link the channels, and Channel 2 in the mixer is showing '-10dB' levels in blue squares - although NOTHING IS PLUGGED IN to the unit.
I now see I can click into the number above the fader though and change that to 0.00dB though.

Turning the middle 'gain' knob UP to maximum (the one above the channel 2 strip) brings the meter down to around -4dB.

Changing the preset knob to 'stereo dj' gets rid of that. So I guess I just need to learn how to use it better.

But still very concerned it is randomly failing to work and getting into an 'update firmware' loop.