Welcome screen error message, missing extensions start folder

[Teri Pettit]

I am getting this error message whenever the Welcome screen is supposed to display. I checked, and sure enough, the extensions folder does not have a start-2.7.2 subfolder. It skips from 2.7.1 to 2.12.1.

It was working fine two days ago. What caused that folder to vanish, and can I get it back from somewhere?

Note: I am still using CC 2019 (on a 2017 MacBook Pro) because I'm still using Mac OS 10.12.6 (Sierra), and I'm still using that OS because I have older apps that are not compatible with newer versions, and I want to keep using them more than I care about having the newer Adobe features.

[kevin stohlmeyer]

What version of Photoshop is this?