What does this compiling error mean?

Today I was compiling PX firmware twice on my windows PC, and was stopped by the same error displayed by the image attached. I really appreciate if somebody could give me an advice. Thanks in advance.

I would kill everything and try again, but add VERBOSE=1.

I’d also highly recommend using Ubuntu or OSX. It’s significantly less painful for PX4 development (even virtualized).
https://dev.px4.io/en/setup/dev_env.html