If you're still running into issues with this, Delete the 1099-R out of TurboTax, then go through Federal Review. Running Review helps to make sure that the program fully reconciles the changes in the return. Once you pass Review without ANY errors, go back to Income section to re-enter your 1099-R and make sure to answer ALL follow up questions. This will resolve your issue.
If all else fails, Call TurboTax and ask for Tax support to assist you. There could be something else that may be causing your issue that they can determine and get resolved for you or they can also walk you through the process as well. Give them a Call: [phone number removed]
