I need to re-enter my SIN number as turbotax has saved my old one. Everytime I try to edit and save my new one, the old one saves and so I can't file my return

If you are auto transferring last year's information at the beginning of your return then all the past name, address, SIN, etc. is coming back. You may need to start a fresh return without transferring last year's information. After you start fresh this year, you will be able to transfer from the correct information next year. 

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