If you are the custodial parent entitled to the exemption and you are not releasing to to the non-custodial parent, just file your return claiming the dependent. If he e-files first, then your return will reject, so you will have to print and mail it.
Both of you will receive your refund if you both claim the child, but within a year or more (the IRS is slow) you will both receive a letter asking if you claimed the child en error and to amend if you did. Do not ignore the letter. Respond that you are the custodial parent entitled to the exemption and you did not release the exemption.
The IRS will follow up with a second letter asking for proof, such as school records, receipts etc, to show that the child lived with you (start collecting that now so that you will have it). After receiving the proof from both parents the IRS will make a determination as to who is entitled to the refund and who must pay it back with interest and possible penalties.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
