I've used the VCP with a ST32F746 Discovery board, which worked without problems.
I now have a Nucleo-H743ZI and I cannot get it to work.
I use Windows 7
The virtual com port shows up in device manager as COM8. I can open COM8 with PuTTY, but the application running in the board appears not to send anything. When I remove the USB plug, device manager shows COM8 disappears and when I plug it in, COM8 shows up again.
In the application, I am using USART3 as described in the Nucleo-144 manual. I send data using the HAL_UART_Transmit() function with the handle address of &huart3.
I know the code is running because the loop sends data and a 200 mSec HAL_Delay() with a LED toggle in the loop. The LED toggles, so I can see that the program is running. Just no data makes it to the PuTTY screen.
The files for the project were generated as a makefile project with STM32CubeMX with my code added into main where the "infinite loop" section for user code is. I've checked the board jumpers (which are default) and everything looks correct. There is nothing connected to either the Arduino connector nor the ST Zio/Morpho connector.