Develop Mode Pixelates - How to fix?

Been using lightroom on the same laptop for about a year now with no real problem. Just last week most images whack out when I enter the develop mode - See example below. I see them fine in the Library and in "F" full screen mode. I do regular updates (on auto update), so I'm using the latest and greatest version.

I followed instructions to set the color profile to sRGB and restarted. Also in the Preferences -Performance screen, cycled through all the GPU setting options. Neither made any difference. 

The only thing that has changed on my end is that I'm normally in the US, but am now traveling. All went well in Rome, and for several weeks in Malta. I don't think this is a factor, just thought I mention any change on my end.  

Any help on correcting this would be appreciated. 

Thanks

Mark