Please see this answer from dmertz:
After clicking the Continue button on the Your 1099-R entries page, did you enter a year-end value that is more than your basis in nondeductible traditional IRA contributions? If you made no traditional IRA distributions other than the amount that you reported as QCD, TurboTax will fail to ask for your year-end balance. You'll need to first enter a QCD amount of less than the full distribution amount, answer TurboTax's questions regarding basis and year-end balance, then edit the Form 1099-R to correct your reported QCD amount.
QCDs can be no more than the amount that would otherwise be taxable if all of the money was distributed from your traditional IRAs during the year. If the amount sent to charity dips into your basis, the portion that is basis must not be reported as a QCD but instead must be reported as a Schedule A deduction. Unfortunately, TurboTax does not do this calculation for you. You'll have to determine the maximum QCD amount yourself, enter that amount as QCD and enter the remaining amount transferred to charity as a Schedule A deduction.
