USB connected only after reset

[Lagodolio]

My H7 board has a strange issue: if I connect it to USB, Windows recognizes it (PRODUCT ID & VENDOR ID are correctly shown) but no communication (by CDC_Transmit_FS()) happens: CDC_Transmit_FS reports me BUSY_USB.

If I reset (by the pushbutton) my board, all is OK, and the communication perfectly works!

After the "hard reset", I can unplug and replug my USB cable and the system works (of course, this is possible only if I use an external power supply).

Thanks and best regards

[MM..1]

Seems on inserting your code hangs on an fault. Debug it ...

[Lagodolio]

Unfortunately, it is not possible to access debugging functions: it is a custom board and I can program it by USB (there is a switch to set "Config Boot System" and to allow me USB programming by STMCubeProg), but STLink / JTAG /SWD Interfaces aren't accessible...