I have Photoshop CC 2014 as well as Photoshop CC installed on my Windows 7 computer. I should probably have uninstalled Photoshop CC 2014 because I only use Photoshop CC. But I did not, and now I have a mysterious problem.
I launch Photoshop from Lightroom 5.7 using ctrl-E or an equivalent menu entry. It has always launched Photoshop CC. Tonight, for the first time, Lightroom launched Photoshop CC 2014! I could tell immediately that something was wrong because of the way my Photoshop workspace was configured. It was configured differently from how I had left it when I last exited Photoshop. Help -> About Photoshop confirmed that the version that Lightroom had launched was Photoshop CC 2014.2.2.
Back in Lightroom, I checked Edit -> Preferences -> External editing tab:
I don't want Lightroom to edit in Photoshop CC 2014. I want it to edit in Photoshop CC, but I don't see a way to tell Lightroom to change this preference.
I tried exiting from Lightroom and restarting, but this did not fix the problem. Lightroom still launches the wrong version of Photoshop.
FYI I have not installed any Adobe updates recently or done any reconfiguring Windows. I use Lightroom and Photoshop daily.