One wrong answer, one missed date, one forgotten trip abroad—and your dream of becoming an American citizen can slip away. Here's what trips up nearly 100,000 applicants every year.

When Immiva's founder was helping his family with their immigration paperwork, they had already paid thousands in legal fees. The lawyers were supposed to handle everything. But when they reviewed the filings before submission, they found 76 mistakes and typos across the applications. From a paid professional.
That's the reality of a system so complicated that even experts get it wrong.
And when you're filing Form N-400, the stakes couldn't be higher. This is your shot at U.S. citizenship. Your right to vote, travel freely, and never worry about green card renewals again.
Here's the hard truth: USCIS denied 86,333 naturalization applications in 2024. That's roughly 13% of all applications reviewed. And most of those denials came from the same handful of mistakes.
The good news? Almost all of them are preventable.
Most N-400 mistakes happen before you even start filling out the form. Getting these basics right will save you months of headaches.
Check your eligibility dates. You can file 90 days before meeting the residency requirement (USCIS Policy Manual, Vol. 12, Part D, Ch. 3). That means 5 years as a green card holder (or 3 years if married to a U.S. citizen). But file even one day too early, and USCIS will deny your application. Use the official USCIS eligibility calculator and add a few extra days as a buffer.
Gather your travel records. Pull your passport, get your I-94 history from CBP, and cross-reference with calendar entries or credit card statements. The N-400 asks about every trip outside the U.S. during the statutory period. Missing even a weekend getaway can hurt you.
Pull copies of all prior immigration applications. USCIS will compare your N-400 against everything you've ever filed. If your addresses, employment history, or travel records don't match, that's a red flag.
Resolve any tax or child support issues. File missing returns. Set up payment plans if you owe money. Bring documentation to your interview.
Check your voter registration status. This one trips up more people than you'd think. More on that below.
It sounds too simple to mess up. But USCIS is explicit: "We will reject any unsigned form."
The N-400 has multiple signature fields scattered across 20+ pages. Miss one and your application gets sent back. Your filing date resets. You've lost weeks of processing time.
How to avoid it: Before sealing that envelope, flip through every single page. Check each signature field. Then check again.
The N-400 asks whether you've ever been "arrested, cited, or detained by any law enforcement officer for any reason."
Notice that word: ever. Not "in the last five years." Not "for serious crimes." Ever.
Many applicants assume a speeding ticket from a decade ago doesn't count. Or that since the DUI was expunged, it never happened. Wrong.
USCIS runs your fingerprints through FBI databases. This is exactly what happens at your biometrics appointment. They capture your fingerprints and cross-reference them against federal records.
If your form says "no arrests" but their background check says otherwise, you've got a credibility problem. And credibility problems can tank an otherwise clean application.
How to avoid it: When in doubt, disclose. Bring court records or proof of payment to your interview. An honest mistake is forgivable. Hiding information is not.
This is one of the most dangerous mistakes, and almost nobody talks about it.
When you renewed your driver's license, did you check a box about voter registration? Many DMVs automatically register people to vote unless they specifically opt out. And non-citizens who register to vote can face permanent bars from citizenship, even if they never actually voted.
The scary part? Many people don't even know they're registered.
USCIS takes this seriously. Under the "good moral character" requirement, false claims to U.S. citizenship (which registering to vote implies) can trigger investigations. In some cases, it can lead to deportation proceedings.
How to avoid it: Before filing your N-400, check your voter registration status on your state's official website. If you find you were registered by accident, consult an immigration attorney immediately. There may be options for "timely retraction," but you need to act fast and document everything.
This section causes more anxiety than any other. Part 8 of the N-400 asks you to list every trip outside the United States during the statutory period. Not just long trips. Every trip.
That weekend in Canada? The quick hop to Mexico? USCIS cares about all of them. And they can check through your passport stamps and I-94 records.
But it's not just about listing trips. You need to calculate the exact days outside the U.S. correctly. The form asks for "days outside," and even a small miscalculation can raise questions about your physical presence requirement.
Trips of 6 months to 1 year create a presumption that you broke continuous residence, though you can overcome this with evidence showing you maintained ties to the U.S. Trips of 1 year or longer automatically break continuous residence, with limited exceptions for qualifying employment abroad (USCIS Policy Manual, Vol. 12, Part D, Ch. 3). And if you're someone who crosses the border frequently for work (living in a border city, for example), tracking all this gets complicated fast.
How to avoid it: Gather your passports. Pull your I-94 history from CBP. Use credit card statements, flight confirmations, and calendar entries to reconstruct your travel. If records are incomplete, you can file a FOIA request with USCIS, though that takes 40+ business days.
You can file your N-400 up to 90 days before you meet the residency requirement. Simple math, right?
Except applicants miscalculate this constantly. One applicant shared that after passing all the tests, the officer rejected their application because they had filed one day too early.
USCIS doesn't do "close enough." If you're short by a single day, you're ineligible.
How to avoid it: Use the USCIS eligibility calculator. Then add a few extra days as a buffer. Better to file a week late than a day early.
USCIS updates forms regularly. Use an outdated version, and your application gets rejected.
The current N-400 filing fee is $710 when filing online or $760 when filing by mail (USCIS Fee Schedule). Online filing saves you $50 and typically processes faster. As of October 2025, USCIS no longer accepts paper checks or money orders. You must pay electronically via ACH transfer (Form G-1650) or credit/debit card (Form G-1450). For detailed payment instructions, read our guide on
How to avoid it: Always download forms directly from USCIS.gov. Verify the current fee using the official fee schedule. Double-check the edition date in the lower left corner of the form.
This is where the game changed. As of October 20, 2025, USCIS updated the civics test. The old 100-question test is gone. The new test has 128 questions.
Here's how it works now:
The test is harder. And most study guides online still reference the old format.
If you're 65 or older with 20+ years as a permanent resident, you qualify for the 65/20 exemption. You only need to study 20 designated questions (marked with asterisks on the official USCIS list). During your interview, the officer will ask 10 questions from this pool, and you need 6 correct to pass. But everyone else faces the new, tougher exam.
You'll need to start over and repay the filing fee ($710 online or $760 by mail).
How to avoid it: Study the updated material. USCIS offers free study materials, and many libraries offer free citizenship classes. Check out our 128 civics questions study guide for the current test format.
If you're a male who lived in the U.S. between ages 18 and 26, you were supposed to register with the Selective Service System. Even if you didn't know about it. Even if you were undocumented at the time.
Failure to register can be a problem for the "good moral character" requirement. USCIS will ask why you didn't register.
If you didn't register and you're still under 26, register now at sss.gov. If you're 26-30, you may be able to register late. If you're 31 or older and never registered, request a Status Information Letter from Selective Service before filing your N-400. If you were unaware of the requirement and can show you didn't knowingly avoid it, USCIS may accept that explanation.
How to avoid it: If you're a man and you're not sure whether you registered, check at sss.gov. If you didn't register and you're still under 26, register now. If you're over 26, request that Status Information Letter before you file.
The N-400 requires "good moral character" during the statutory period. Two things raise immediate red flags: unpaid taxes and failure to support dependents.
Debt alone isn't disqualifying. But willful failure to pay what you owe, especially to the IRS or your children, suggests you don't meet the moral character standard.
USCIS uses a "totality of circumstances" approach for evaluating good moral character (USCIS Policy Manual, Vol. 12, Part F). Officers consider positive contributions (volunteering, community involvement, caregiving) alongside any negatives. This means you can strengthen your case by documenting the good things you've done.
How to avoid it: File any missing tax returns before applying. If you owe taxes, set up a payment plan and bring documentation. For child support, make sure payments are current. And consider bringing evidence of positive community contributions to your interview.
If your record was expunged, sealed, or dismissed, you might think it "doesn't exist" anymore. Not for immigration.
USCIS explicitly states you must disclose all criminal history, regardless of outcome. Expungement doesn't erase arrests from their databases. Your A-Number links all your immigration records together, and USCIS will cross-reference everything.
How to avoid it: Get copies of all court records. Disclose everything. If you have criminal history, consider consulting an immigration attorney before filing.
Many applicants submit N-400s with blank fields, missing pages, or without required documents like green card copies, marriage certificates, or divorce decrees.
When USCIS receives an incomplete application, they'll issue a Request for Evidence (RFE), delaying your case by months. Or they'll reject it outright. With the current USCIS backlog exceeding 11 million cases, you can't afford additional delays.
How to avoid it: Use the USCIS checklist for N-400 supporting documents. If documents aren't in English, include certified translations.
USCIS compares your N-400 against every prior application you've filed. Green card petition, travel records, tax returns, employment history.
If your N-400 says you've lived at three addresses but your green card application listed four, that's a problem. Mismatched information looks fraudulent, even when it's just carelessness.
How to avoid it: Before completing your N-400, pull copies of all prior immigration applications. Make sure your answers match or have reasonable explanations for any changes.
Here's something most guides don't tell you: you can fix errors at your interview. If you catch a mistake before your interview date, bring a corrected addendum with supporting documents. The officer will note the changes in your file.
Be upfront about it. Don't wait for them to find the discrepancy. Volunteer the correction at the start of your interview. Officers appreciate honesty, and an applicant who proactively fixes an error looks much better than one who seems to be hiding something.
If the officer finds an error you didn't catch, don't panic. Stay calm. Explain what happened. If it was a genuine mistake rather than an attempt to deceive, you may still be okay.
If your N-400 is denied, you have three paths forward.
Option 1: Appeal with Form N-336. You have 30 days from the denial to file an appeal. This costs $755 and gets your case reviewed by a different officer. Appeals work best when you can show the original officer made a factual or legal error.
Option 2: Refile. Sometimes it's faster and cheaper to just submit a new N-400 with corrected information. This makes sense if the denial was based on a fixable issue like incomplete documentation.
Option 3: Wait. If the denial was based on something that will change with time (like not meeting the physical presence requirement), sometimes the best move is to wait until you clearly qualify and then refile.
A denial goes on your record, but it doesn't automatically prevent future approval. The key is understanding why you were denied and addressing that issue directly.
For straightforward cases, you probably don't need a lawyer. If you've been a law-abiding permanent resident for the required time, have no criminal history, no complicated travel, and no tax issues, filing without an attorney makes sense.
But there are situations where legal help is worth it.
You should talk to an attorney if you have any criminal arrests or convictions (even dismissed ones), complicated travel history or extended absences, tax issues or unpaid child support, if you've ever claimed to be a U.S. citizen by mistake (like voter registration), or if you have inconsistencies between your N-400 and prior applications.
An attorney can help you understand your risks before you file. And in complicated cases, that knowledge is worth the higher cost.
Here's what actually gets N-400 applications denied:
An N-400 denial means losing your filing fee ($710-$760), waiting months to reapply, and explaining the denial on future applications. In some cases, it triggers USCIS scrutiny that reopens old files or initiates removal proceedings.
Most mistakes are preventable. They happen because the N-400 is 20 pages of legal language and gotcha questions. They happen because even paid professionals miss things, like the 76 errors Immiva's founder found after paying thousands in legal fees.
Immiva catches these errors before you submit, for .
Our platform walks you through every question in plain English, flags inconsistencies in real time, and calculates eligibility dates automatically.
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If you catch it before your interview, bring a corrected addendum with supporting documents. The officer will note changes in your file. Be proactive about it.
Unlikely, unless it involved alcohol, drugs, or an arrest. But you still need to disclose it. Not disclosing is worse than the ticket itself.
You'll retake it within 60-90 days. Fail again, and you must refile and repay the fee. With the new 128-question format, study hard.
You get two attempts. After two failures, your application is denied and you need to start over.
Usually no. A simple denial for things like test failure or incomplete forms doesn't trigger deportation. But if the denial uncovers fraud or false claims to citizenship, that's different. Those situations can lead to further scrutiny.
For straightforward cases, no. But if you have criminal history, complicated travel patterns, or any of the red flags mentioned above, consult an attorney first.
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This guide is based on current USCIS policy and federal regulations. All information was verified against these official sources:
Immigration law changes frequently. We monitor USCIS policy updates and revise this guide when regulations change.
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