Why IRIS rejects your CSV, and how to fix each error
The IRIS Taxpayer Portal rejects CSVs for scientific notation, ZIP codes, line breaks, extra spaces, periods and #, $0.00 and empty checkboxes. Each cause, with the fix.
You downloaded the IRS template, filled it, uploaded it, and the IRIS Taxpayer Portal said no. Publication 5717 explains that there are two kinds of errors, and lists the conditions that most often get CSVs rejected. Here's each one, what it looks like in your file, and the fix.
File-level vs field-level errors
File-level errors mean the portal couldn't validate the template, and only one shows at a time. Field-level errors flag specific cells, and they all show at once. Fix the file-level errors first: wrong or reordered columns, extra commas at the end of lines, more than 250 records, or more than one tax year in the file.
The common causes, with fixes
| What IRIS dislikes | Looks like | Fix |
|---|---|---|
| Scientific notation | 5.12E+08 in a TIN or amount | Format the column as Text before typing. If the digits are already lost, re-enter them from the source. |
| Dates in other formats | 3/7/25, 2025-03-07 | Use MM/DD/YYYY. Two-digit years are not accepted. |
| ZIP code formatting | 2110, 33701-2210 | Keep leading zeros (02110) and don't use a dash in 9-digit ZIPs (337012210). |
| Line breaks inside cells | Address on two lines in one cell (Alt+Enter) | Put the second line in Address Line 2. |
| Leading, trailing, double spaces | " Acme LLC " | Trim and collapse spaces, and empty "blank" cells completely. |
| Periods or # in names/addresses | Acme, Inc., Ste #4 | Acme Inc, Ste 4. |
| Mixed tax years | 2024 and 2025 rows | One template per tax year. |
| $0.00 or blank-looking cells | 0.00, $0, a space | Leave money cells with no amount completely empty. |
| Empty checkboxes | Blank "2nd TIN Notice" | Checkbox fields need Y or N. |
The IRS's own IRIS Working Group decks describe the same pattern from the other side: CSV uploads failing on template format, TIN formats and special characters.
Have the CSV already? Check it free: every cell against the IRS rules, safe fixes applied automatically, right in your browser.
Check my CSVStop Excel from breaking it again
- Before entering data, select all columns and set Number Format to Text.
- Save as CSV UTF-8 (Comma delimited).
- Don't reopen and re-save the CSV in Excel. Pub 5717 warns that reopening removes your formatting. Make last-minute edits in a text editor.
- Don't copy-paste from another CSV into the template, because the formatting carries over (also from Pub 5717).
Errors that aren't in the IRS table
- TIN without dashes. The guidelines require
XX-XXXXXXXfor EINs andXXX-XX-XXXXfor SSN/ITIN/ATIN, and the TIN Type has to match. - Name Type mismatch. If Name Type is
B, Business Name Line 1 is required; ifI, First and Last Name are required. - Field too long. Address lines allow 35 characters and business name lines 40.
- Country and state codes. IRIS uses IRS country codes, which aren't ISO codes. Germany is
GM, Spain isSP, the Dominican Republic isDR. US states must be 2-letter abbreviations. - 1099-NEC with no amount. Box 1 needs an amount, or Box 2 must be
Y.
IRIS CSV checks all of these, plus each form's own columns, and fixes what can be fixed safely (formats, spacing, characters, codes). It flags only what needs a human, like a TIN that Excel already truncated.
Sources
- IRS Publication 5717, IRIS Taxpayer Portal User Guide (Rev. 9-2026)
- IRS IRIS Working Group meeting deck (Feb 12, 2025)
- IRS: E-file information returns with IRIS
FAQ
What is a file-level error in IRIS?
A file-level error means the portal could not validate the template at all, for example wrong columns, extra commas, a mixed tax year or a non-IRS template. Only one file-level message shows at a time, so you may fix one and get the next.
What is a field-level error?
A field-level error points at specific cells (like an invalid TIN or ZIP). All field-level errors show at once in a table.
Why does my CSV look fine in Excel but fail in IRIS?
Excel hides problems: it displays rounded numbers and dates in your locale, and re-opening a CSV re-applies General formatting, which turns long numbers into scientific notation and strips leading zeros. Check the file in a text editor or with a validator.