If your IRA Information Worksheet in the 2023 TurboTax tax file that you transferred into 2024 TurboTax to begin your 2024 tax return shows your basis, the only reason that your basis would disappear from your IRA Information Worksheet in 2024 TurboTax is if you inadvertently answered No when 2024 TurboTax asks if you have basis in nondeductible traditional IRA contributions. If you answer No (which I believe is the default answer if you just click the Continue button without changing the answer to Yes), TurboTax will silently delete your basis information, without asking for any confirmation. Over several years I complained about this deficiency in TurboTax but my concern was ignored and a confirmation to delete basis information was never added, generally blaming the problem on user error. I finally gave up trying to get the TurboTax developers to make this simple, important change.
