It sounds like there's an error in the state tax withholding reported on your W-2. You'll need to get in touch with the employer that made the mistake and request a corrected W-2 reflecting the accurate state withholdings. Notify them about the error and explain that you were a full-time resident of New York during the year, so they can make the necessary adjustments. Once you receive the corrected W-2, you can use it to file your state tax returns properly. Remember to file a nonresident return for California to report the corrected income (if required) and a resident return for New York showing your complete income for the year. The corrected W-2 will help ensure you're credited for the appropriate state tax withholdings and avoid any issues when filing your state tax returns.