Photomerge doesn ́t complete merging if using dng files. All files will be loaded as layers and things goes on, but final result will never be available. Photoshop reset won ́t fix the problem, nor reboot. With nef files, works fine.
Yes, at least three times, by pressing shift-option-command while starting Ps. Also after every reset reboot (I ́m using iMac with i5 Intel processor). Generally, I have browsed this help site and done all those tricks which I have found concerning this topic.
I know that nef is similar file with dng, but fact is that with nef, merge works as it should but with dng it doesn ́t.
I can live with this, but somehow I feel uncomortable with things being like this. I really like panorama pictures and because of my photography studies I ́m kind of forced to do those pretty much in a near future.