I have the same problem, a spinning blue circle. I tried all the fixes on the forum to no avail. I have had two screen sharing sessions with Adobe help team both just dithered about the screen without offering any solutions. One said leave it for a couple of hours and if it still occurs get back to us (I'd already told him it had been going on a week so what's another two hours going to do!) the second one said she would have to consult with other help experts and get back to me. Hey ho I got an email saying case closed! Meanwhile Lightroom CC is useless to me, Adobe are happy to take my subscription every month but seem unable to help, so actually I'm paying for something that doesn't work!