(after fighting with an issue not being able to login to this server for the last couple of weeks) There is no .log file. I couldn't believe it. Kinda amateur hour, but anyway.
Today CubeIDE had 1.13.0 available, so I updated and the out of memory error is gone. But the update, and updated firmware file for L4, completely borked my project and a simple printf goes to a fatal error without calling _write, and if I create a new project that just uses the same UART and has the same _write function, it works like a charm. It's a hot mess.
If there's no log file: open a terminal and copy there the command line that starts CuibeIDE (or run it in a Terminal). Will it spew something to stdout/stderr?