I'm running Lightroom 2015.3 with the most recent update of Windows 10 and it becomes unresponsive when 1:1 previews are being generated or at other random times requiring me to kill the applicaiton. I've been using Lightroom since beta version 1 and the latest 2015 updates are some of the buggiest I have ever used.
Sorry, this has nothing to do with my problem. The application becomes unresponsive, with the spinning mouse cursor requiring me to kill it. I understand that previews take a long time to render.
I will try uninstalling and reinstalling the application to see if that helps.