When box 2a contains UNKNOWN, it means that your retirement administrator didn't calculate the tax-free portion of your distribution. TurboTax will lead you through the process to determine the taxable amount.
Refer to the TurboTax article Is my distribution nontaxable if Box 2a on my 1099-R is 0 or blank? taxable portion will need to be calculated.
[Edited 3/3/25|1:04pm PST]
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