This is a little clunky but it worked for me. We have a taxable account and an IRA at a brokerage. Separate user name and password for each. I downloaded the taxable account first. After that download I was not given the option to use a different user name and password. The taxable account just kept getting downloaded. I then changed my default browser. I prefer Firefox but changed the default to Chrome. I then repeated the import/download in TurboTax. When the browser opened in Chrome it prompted me for a username/password and I was able to get the IRA information.
As somebody pointed out it might have been quicker to just enter the information manually but I wanted to make it "work."
