I recall editing some config or setting something somewhere a month or so back to enable extra logging or messages in RetroArch. When I start/stop RetroArch I get a black window popup with a bunch of what looks like logging details, and this disappears. I don’t recall where I set this or how to turn it off, but… how do I turn this off?
I found it, it was the log_verbosity setting in the config file. I guess I set it to true at some point while troubleshooting and forgot to set it back to false afterwards. Screen is gone now!