You need to turn off the Graphics Processor from the Lightroom Preferences.
Go to Lightroom Preferences from the Edit menu
Click on Performance tab
Uncheck the Graphics Processor
Let us know if that helps.
Why isn't Lightroom able to use the GPU? I have just updated as well and am getting random crashes when doing certain tasks. I have set LR to auto report any issues. This is a bit frustrating to be honest.
My Lightroom is still crashing and I have a compatible GPU also if I disable the GPU LR allows me to clone out hot pixels otherwise it crashes.