The first thing to try is go to your Lightroom preferences, Performance tab, uncheck the GPU option.
Spent 3 hours on the phone to adobe they can't do anything!
Other than use version 5.
Capture 1 looking good !
Sent from my iPhone
Please provide us some information about your Computer so that we can check what could be the issue.
Post the system info from Lightroom Help>>System info report here.
Computer- mac pro ,late 2013, 32 gig ram,Yosemite 10.10.05
Worked fine before last update.
Suspect GPU causing problem.
GPU unchecked in preferences still no difference.
It,s due to the update.
Last update to LR re- bug fixes made no difference.