Nothing dramatic here ; Just unable to get Audio / MIDI engine started .
Tried ALSA and Jack options .
QJackCtl says it can’t start the driver, so most likely it has nothing to do with Ardour as this problem happens also with Cockos REAPER .
The board is a 3 B+ .
Operating system is Raspberry Pi Desktop OS 64 bit and on a second SD card I’ve installed the same OS as Lite version, that I’ve upgraded to Desktop OS afterwards .
Audio Interface is Behringer UMC202HD, that performs as it should in “normal” Linux installations .
Then probably linux-audio-users mailing list would be a better place to get help with general ALSA problems. Ardour (and any other audio application) rely on the ALSA driver working with the device properly.