Blank screen when doing an amended return - trying to add a 1099B

I'm using Mac Desktop Turbotax Premier (latest update).

 

We received a late 1099B, so trying to do an amended return. On the page on Wages & Income / Stocks / Add more sales / Stocks (1099-B). When I press Continue on this screen I end up on a blank page where I can't do anything. 

 

Not sure how to proceed.