You are always eligible to contribute and deduct your employer-sponsoered 401k. The retirement plan box helps determines how much you of your IRA (IRA, not 401k) that you can deduct. The retirement plan box won't matter AT ALL if your income is within these limits: <a rel="nofollow" target="_blank" href="
https://www.irs.gov/retirement-plans/plan-participant-employee/2016-ira-contribution-and-deduction-l..., if you are planning on making an IRA contribution, but are concerned that it may NOT be deductible (due to the retirement plan box), then you should contact your payroll/HR department to verify which W2 is the correct one. If it's the printed one, then delete the imported W2 and reenter manually (without that box checked)
