My HSA Contributions in block 12d, with a code of W, are coming up as taxable income on my return. Why would this value be taxable?

[glhirsch]

Last year this was not a taxable income.

[MonikaK1]

Contributions to an HSA can appear to be taxable until you follow the steps to complete the HSA interview in TurboTax, which will then generate a completed Form 8889. Form 8889 is used to:

• Report health savings account (HSA) contributions (including those made on your behalf and employer contributions).
• Figure your HSA deduction.
• Report distributions from HSAs.
• Figure amounts you must include in income and additional tax you may owe if you fail to be an eligible individual.

See here for more information from the IRS about Form 8889. 

[Opus 17]

Your HSA contributions are assumed to be taxable until you run the full interview and tell the program that you had qualifying HDHP insurance.