Better BibTex doesn't work by showing "Better BibTex is loading"!
After updating Better BibTex, I just see "Better BibTex is loading" in Preference window. When I return to some previous versions, the Citation keys of all documents have vanished, and Zotero shows "an error has happed, please restart...."
I ended up with a workaround by uninstalling the PubPeer add-on on the computer where BBT did not work, which would get BBT to work again. Eventually, the solution for me was to uninstall every add-on for good, restart, and reinstall them in a given order. (I think BBT first.) Everything works now when the context menu shows Better BibTeX first.
I may be completely wrong about this, but I have all my add-ons working now, so it can't hurt to try?