If you were not a resident of Connecticut for any part of the year and you did not work in Connecticut at all during the year but Connecticut income tax was withheld by your employer or by a pension plan payer, you must complete Form CT-1040NR/PY, for the year in which the tax was withheld and attach a copy of Form W-2 or Form 1099-R showing Connecticut income tax withheld. You should discuss the error with your employer or payer so that the same does not occur for the following year.
Completing the Return
If income tax was withheld from your pay or pension in error, you must file Form CT-1040NR/PY to request a refund. Complete Lines 1-5 following the directions on the form. Enter “0” on Line 6 if you had no income from Connecticut sources.
If you are filing a paper return, attach a statement to the front of the return explaining that you were not a resident for any part of the year and that you did not work in Connecticut during the year along with a copy of the Form W-2 showing $0 Connecticut wages and the amount of Connecticut income tax withheld. If the W-2 from your employer shows Connecticut wages, then your employer must also issue to you a corrected W-2 showing $0 Connecticut wages, proving that you did not earn any of your income while working in Connecticut. (If you file electronically, retain this statement with your records. You may be required to provide this documentation after you file.)