The OS is Windows 11. I tried DfuSe and it couldn't find it either, but STMCubeProgrammer does see it so I'll try with that.Thanks for your help.

Yes, it is in DFU mode and showing in device manager but the software can't find it.

Actually I'm having this issue with the STEVAL-IDB008V2 not the X-NUCLEO. I can upload the DTM_UART.hex as described in the documentation but the GUI software is then unable to connect to the device in DFU mode after displaying the popup shown above ...

I'm facing the same issue. Did anyone find a solution? @paul19​ @a28j​ Note: @Silvio​ Baud rate is not the issue as DFU is not using the serial port.