I accidentally filed my Federal taxes twice; once by e-file and once by mail on this site. How do I make sure only the e-file goes through?

[Melaine]

If you did not print and mail your return to the IRS or State, only the e-file will go through.  However, if you did mail it in as well as e-filed, both will be sent to the IRS where they will contact you regarding the error.  While this can be resolved, it will delay your refund if you were expecting one.