Hello, when I try to finalize my tax return, it denied me because it said someone with a duplicate Social Security number had already filed

First, double check to be sure you entered the right number.  Typographical errors can happen sometimes.  

 

Then, if you are married, be sure that your spouse has not already filed a joint return including your information.  

 

If neither of the above situations applies to you, you may be a victim of identity theft.  Take a look at the TurboTax article below for some advice about what to do next.  There is also a link for further information from the IRS.

 

Identity Theft: What to Do if Someone Has Already Filed Taxes Using Your Social Security Number

 

When to file an Identity Theft Affidavit