Thank you for your response. Form 8606 was filed in 2010, 2011 and 2012; the nondeductible traditional IRA contribution carried over from 2010 to 2011, but did not carry over in 2012. Also, I did not file 8606 in 2013-2016, as there was no nondeductible amount (now I'm not sure if I should still file 8606; only to show total basis in traditional IRAs). I may file 8606 for 2017, so I'm hoping I can enter carried over amounts, from these previous years, at this time.
