I amended my return but when transmitting I get an error saying it's a duplicate of the previous transmission and to contact customer support

[cjbaker790]

Missed a 1099-INT, selected the "amend a return" option when starting TurboTax, added the information, clicked through to "transmit", then got the error saying it's a duplicate transmission.

[xmasbaby0]

You did not amend correctly--  You just messed up your original return and need to restore it to exactly what it looked like when you e-filed it.

It is too soon to amend a 2024 tax return.   You have to wait until it has been fully processed by the IRS.  Sometimes the IRS catches and corrects mistakes you made.   And the Form 1040X you will need is not available until mid-February.  Amending too soon can cause confusion and long delays.