Cubase artist 12, export to .wav and .aif is empty

Cubase 12 does not do batch export.

I’ve been exporting stems from a multi-track recording, sometimes it works, sometimes it doesn’t. The procedure is always the same, select and solo a track, mute all others, select .wav or .aif, export to existing folder. The files show up there, but there is no content, empty. I’ve tried many times, once in a while a stem does get exported properly.
I can’t check in between with Audacity, because for some reason Cubase freezes up.
What is wrong?

Are you sure that the Monitor button was always disabled in the involved track header, before opening the Audio Mixdown window ? Because, if activated, you’ll indeed get a completely flat audio file. I’ve been trapped more than once in the past, with that one…

Monitor is not on. It’s very weird. The saved .aif file is 31.4MB, way too small, thus empty. I try to right click, “Open as…” to play it in Audacity, at that moment everything freezes. I’ve done this several times, always the same result.