APple photos no longer exports?

So here's the situation - yesterday I dutifully did the Photos upgrade as urged by my iMac. I am running Catalina 10.15.7.

Today, after selecting a few photos and choosing to Export, the first dialog box appeared as usual, but the second dialog box did not. That's the one that showed into which folder the exports would go.

And lo and behold, it seems nothing got exported. I tried both kinds of export (which previously would default to sending the exported images to two different folders) but now, nothing.

Anyone have any ideas?