Just had this same problem. After much searching I found the solution. Go to VIEW in the menu bar and select FORMS. About half way down you should see one or more FORM 1099-DIV (place where dividend came from in parenthesis). Click this and look at the name on THIS form. If you have more than one then look at all of them. Find the one with the longest name and find a way to abbreviate it. The name isn't really important. The tax ID# is. The name just has to fit. Click on another box so it saves it and exit the form. Go to VIEW in the menu bar again and select STEP BY STEP at the top and it should return you to the smart checker again. Rerun the check. You should be good.
My exact situation was this name:
Walmart Inc c/o Computershare
29 characters is too long so I shortened it to:
WMT c/o Computershare
All good then. The limit is somewhere between 21 and 29... My guess would be 25 but it's only a guess.
