I filed my dependent daughter's taxes first. I didn't check the box for "I can be claimed as a dependent". She already received her return. ine got rejected

[cletizia]

Mine was rejected due to two different returns with the same SSN (Hers).  How do I file mine electronically?

[Carl]

Bottom line is, you will not be filing your return electronically this year, unless you remove your daughter as a dependent from your return. Once the IRS computers have an SSN marked as claimed for the tax year, that's it. That SSN can not be claimed on any other e-filed tax return for that same tax year. No matter what you do.

Your daughter will need to file an amended tax return removing her self-exemption. THis means she will be paying some of her refund back to the IRS. Per IRS rules an amended return can not be e-filed. She will have to print it, sign it (both the 1040 and 1040X) and mail it to the IRS. Amended returns take 8-16 weeks to process.

For you, if you will be claiming your daughter as a dependent on your tax return, you have no choice but to print, sign and mail your return too. It just flat out will not be possible for you to e-file this year.

Make sure you mail the daughter's amended return and your return in separate envelopes too. Otherwise, it's a sure bet that one of them will not be processed if you include them both in the same envelope.