If you have lost your W-2, get in touch with your employer and request another copy. If there isn't enough time to get one before the filing deadline, use the information from your last pay stub for the year, and fill out Form 4852 (substitute W-2 and 1099R, available from the IRS). If you've lost receipts or bills, reconstruct them as completely as you can. If additional information becomes available later, you will need to file an amended return 1040X.

Note: Our program does not produce form 1040X.