Comment by inferiorhuman

Of note neither the debugger nor user USB port on that board work with ARM Macs (guess how I found that out). You can connect it to a hub as a workaround but that may lead to data corruption (per the errata).

Also worth noting that the discrete STLink V3 dongles also use the F7 for USB stuff.

Also also worth noting that not all of the Embassy examples are set up to work with Nucleo boards. It's an odd choice but it is what it is.