After you file

There are many issues that can delay refunds, including ones over which the IRS has no control. Here are the top three categories:

Administrative requirements

• Earned Income Tax Credit and/or an Additional Child Tax Credit. If you filed in February or earlier and claimed either of these credits, the 2017 PATH Act requires processing to be delayed.
• Form 8379 (Injured Spouse Allocation). If you included this form on your return, it can take 11–14 weeks to process.
• Form 1040-X (Amended Return). If you amended your return, it can take 12–16 weeks to process.
• Refund offset. The IRS may have discovered you have delinquent debts, which they're legally required to deduct from your refund. You'll receive a notice about the offset.

Missing, inconsistent, or suspect information

• The IRS found errors, inconsistencies, or missing info on the return. For example, you and a former spouse both claimed the same child as a dependent.
• The return is under review, which can happen randomly.
• The IRS suspects identity theft or fraud.

Delivery glitches

• Your refund check could just be delayed in the mail. The reason could be as simple as a new postal carrier learning your route.
• Electronic payments may be delayed by bank transfer and posting issues.

Please see this TurboTax FAQ for more information, What if my IRS refund is taking longer than 21 day...