Try going back to your W-2 summary screen, or the deleting a form screen as listed below to remove the duplicate entries.
If you need to remove a W-2:
1.
Go to "Federal Taxes" at the top of the
screen
2.
Select the "Wages & Income" sub-tab
3.
Select "Start/Revisit" next to "Wages and Salaries"
4.
Select "Delete" next to the W-2 you would like to remove
To remove a W-2 in TurboTax Online:
1.
Go to "My Account" in the top right corner
2.
Select "Tools"
3.
Under "Tools Center" select "Delete a Form"
4.
Navigate to "Form W-2(the duplicate)"
and select "Delete" next to it