Write image to SSD drive in hot swappable server case: issue

It’s my first Home Assistant install. Following the instructions, in my Windows PC, I placed the eventual Home Assistant SSD drive in one of my two SSD drive bays. The drive is visible in Windows. I then installed Balena Etcher and added the required URL to download the image file. Then I click Select Target, but I don’t see any options apart from Plus a target drive.

Does my SSD have to be attached to my PC via USB and not as a mounted drive in Windows? Is the hot swappable drive bay the problem?

I suspect your drive bay - or the driver for it - is not presenting the drive as “removable media”. One way to determine that is if there is an eject option available if you right click on the drive icon.