If your 1099-R form shows "UNKNOWN" in box 2a, follow steps below:
- Leave Box 2a Blank: When entering your 1099-R information in TurboTax, leave box 2a blank.
- Check Box 2b: Check the box for 2b indicating "taxable amount not determined"
- Follow-Up Questions: TurboTax will prompt you with follow-up questions to help calculate the taxable amount
For more detailed guidance, you can visit the TurboTax Community