Thank you! I had the same problem with the blank pop-up screen and I do use an external monitor. I maximized the Turbotax window as you suggested, and continued from there, but the popup screen was still blank. Then I noticed a display in the lower right of the screen showing that I could increase my font size from 100% to 110% so I clicked on the 110%... and then the blank popup screen filled in and I was able to proceed. I dunno what to think, but you definitely pointed me in the right direction.
