Find the most likely cause of an IRIS CSV upload problem.
Choose what is happening in the IRS IRIS Taxpayer Portal and get a focused troubleshooting plan. The tool covers portal upload behavior plus common CSV formatting problems documented in the IRIS user guide.
✓ No tax data is required for this toolWhat problem are you seeing?
Select the symptom that best matches what you see. You can change the selection at any time.
Three tools to use before retrying the portal.
Start with the file itself, then retry IRIS after you have ruled out structural and formatting problems.
Validate the CSV
Compare the final CSV against the expected form layout and catch common hazards.
Open validator →Run the formatting checklist
Review UTF-8 saving, identifiers, dates, header structure, and final-save risks.
Open checklist →Start from the correct template
Open the template library for the form you are preparing.
Browse templates →What the IRS currently tells filers to check
Why does the IRIS Start button stay inactive after I upload a CSV?
The IRS says to confirm the file is saved as CSV and that the file name appears in the blue Current Uploaded File box. If it does not appear, refresh the page and upload again. If it appears and there are no issues, the Start button should become active.
What if IRIS keeps spinning after I choose Add All?
The IRS recommends refreshing the page, returning to the Taxpayer Portal dashboard, and checking the Unsubmitted Forms tile. If the forms were not uploaded, retry the upload before calling the Help Desk.
How many records can a CSV contain?
Publication 5717 (Rev. 2-2026) says a CSV file can contain up to 250 forms, while the IRS IRIS overview page currently describes the portal as able to e-file up to 100 returns at a time. Because those pages are updated independently, check the live portal and current instructions for the workflow you are using.
Why can Excel create IRIS errors even if the worksheet looks correct?
Spreadsheet software can reinterpret dates, identifiers and long numbers. Publication 5717 specifically warns about scientific notation and date reformatting and recommends checking the final CSV itself.
Official references: IRS IRIS guidance and helpful hints · Publication 5717 · IRIS known issues and solutions.
Open a form-specific CSV error guide.
Use the exact column count and form-specific field checklist for the file you are preparing.
Need to fix a return after submission?
Use the IRIS Correction Center for accepted-return corrections, rejected-transmission recovery, and form-specific correction guides.
Move from a free check to the complete 1099ERICH workflow.
The free tools help diagnose individual filing problems. 1099ERICH is the $299 Windows desktop workflow for importing CSV or Excel data, validating records, printing recipient copies, and creating IRIS-ready CSV files.