Thanks all for sharing your thoughts.
I use Turbotax Online, which seems to be different from yours.
With the help of an EA from Turbotax Live, the final solution is to mark the distribution as Rollover to tell Turbotax that it is as nontaxable. A "conversion to Roth" would have triggered Turbotax to treat it as taxable, no matter how I tried to mark the original contribution as non-deductible.
