When I'm typing an email address in the LR CC export box, the page suddenly dumps me out to a full loupe image of the photo I want to email. It might have something to do with the letter "l" in the email address. It happened three times in a row. I have Sierra on my MacBook Pro.
You can turn off the Graphics Processor from the Lightroom preferences, else reinstall it via creative cloud.
Let us know if that helps.
It worked. I am unable to see the “Correct” choice below the answer as directed below.
Great, Thanks for the feedback.