No import thumbnails for D40 NEF files

Hello all,

Very new to not just digiKam but open source. I just downloaded digiKam for macOS 7.1 and am stumbling through learning it. One thing I can’t figure out: how to make thumbnails appear in the import window.

I’ve tried different Image Editor Settings without effect.

I’m on a 2-year old machine running Catalina, and I’m importing NEF files (raw only, not raw+jpg) from a Nikon D40. Maybe those files are not supported? Or it’s a bug?

I can see this will be a long journey. Any help is appreciated.