Hello, I just installed STM32CubeIDE & tried to build my 1st blinking led with a cheap STM32F030, but, although the .elf was generated, I could not get it to the board -> "localhost:3333: The system tried to join a drive to a directory on a joined drive".

[KnarfB]

That's bad, the error message is nonsense. 3333 is the default port for OpenOCD debugger. You can change that to ST-LINK GDB server in the Debug Configuration> Debugger tab and retry. Common causes for trouble are: use of spaces, umlauts or other special (non alphanumeric ASCII) characters in path names.

You could also try a clean reinstall. Clean means that, after uninstalling, you manually delete (or move to a save backup place) the STM32CubeIDE folder (C:\ST\STM32CubeIDE).

Finally, you can check if you can access the board from the STM32CubeProgrammer tool.