Naturally, I didn't copy the Apple Article number but it's title is "Installer destination window does not show drives."
The "solution" is to "wait a while"! It also says that the larger the volume, the longer that "while" may be.
As an "advanced" solution, they suggest doing an fsck 'status check.'
In Terminal, execute the following command:
ps auxww | grep fsckI have no idea what that does, I thought 'grep' was a tool used to find/change text!