I recently installed the latest versions of LR classic & the new photoshop update. Before that I had never had a problem clicking Photo, then edit and then selecting Open as Layers in Photoshop. Now that option is grayed out. I have selected five photos so that is not the problem. I am worried that this is a result of the new configuration or relationship between LR and Photoshop. Anyone having the same problem? I am windows 10.
First up, in LrC, in Preferences, in the External Editor tab, is the correct Photoshop listed? Some have had an issue with that being incorrect, uninstalling OS then reinstalling PS corrected.
Second, a change in the way Adobe Creative Cloud Desktop App (ACCDA) behaves when updating PS, may have caused you to overlook that Adobe Camera RAW did not get updated (used to come along for the ride during PS update, even if you did not click on it to get updated, so some ignore). In PS, and in ACCDA make sure you have ACR 14.
Previous versions of LR have had this problem, but Adobe said they fixed it back in March. Triple-check that you actually have "the latest" version by doing the menu command Help > System Info -- are you running version 11?
While waiting to get this resolved, see this post for a workaround: