Scrivener can't detect installed Kindle Previewer 3

Steps taken to produce a novel in MOBI format for upload to kindle. Using Scrivener (3.1.2)for Mac

  1. click compile
  2. Select Kindle e-book (mobi)
  3. Message pops up that I need to install KindleGen from Amazon’s website with a direct link.
  4. Link opens Amazon page for Kindle Previewer 3 install (which I think has replaced KindleGen)
  5. I install Kindle Previewer 3 in my Applications folder. I open it successfully.
  6. I return to Scrivener and click Choose to allow it to use Previewer 3.
  7. The Previewer 3 icon is not selectable in the file window that opens. It is greyed out and unable to be selected.

What am I doing wrong?

Upgrade to the latest version of Scrivener for Mac OS (3.1.5) as 3.1.2 is a few updates behind, and see if that helps it detect the version of KindleGen included with the Previewer bundle.