Amazon Flat File Processing Errors: The Complete Guide

You uploaded a flat file to Amazon. The processing summary came back with errors you do not recognise, warnings you are not sure matter, and a handful of rows that seem to have vanished entirely. This guide walks through what the processing summary actually tells you, the most common error codes and what causes them, and a systematic approach to fixing a failed upload without guessing.

What the processing summary actually is

After every flat file upload, Amazon generates a processing summary. This is a tab-separated report that lists the result for each row in your file. You can download it from the "Monitor Upload Status" page in Seller Central, usually within minutes of a small upload completing.

Each row in the summary corresponds to one SKU from your file. It shows the SKU, the result (Success, Error, or Warning), and a message describing what happened. The message includes an error code, a plain-English description (often vague), and sometimes the specific field or value that caused the problem.

If your summary has fewer rows than your uploaded file, the missing rows were not received by Amazon. This usually means corruption during the export from Excel to the tab-delimited format, or rows that were accidentally deleted when editing. Amazon cannot return an error for a row it never received.

Errors versus warnings

This distinction matters more than most sellers realise.

• Errors mean the row was rejected. Nothing changed for that SKU. You must fix the error and re-upload for the change to take effect.
• Warnings mean the row was processed, but Amazon flagged something. The change went through, but the flagged issue might cause a suppression or catalogue problem later. A warning about a brand name mismatch, for example, can lead to listing suppression days after the upload.

Treat warnings as errors you have not been punished for yet. Fix them in your next upload rather than hoping they resolve themselves.

The most common error categories

Amazon flat file errors fall into a handful of recurring categories. Within each category, the fix is usually the same pattern applied to every affected row.

Missing required fields (error 8058)

Error 8058 fires when a field Amazon considers mandatory for your product type is either blank or missing from your file entirely. The tricky part is that required fields vary by product type: a field that is optional for "Home and Kitchen" might be mandatory for "Beauty." The error message usually names the missing field, but the field name in the error does not always match the column header in your template.

The fix: check your product type definition in Seller Central for the list of required fields, then populate every one of them. See our full guide to error 8058 for a walkthrough.

Product ID mismatch (error 8541)

Error 8541 means the product identifier you provided (UPC, EAN, or GTIN) does not match what Amazon has on record for that ASIN. This happens most often when sellers use a generic barcode purchased from a third party, or when the same ASIN has been updated by another seller with a different barcode. It also fires when the Product ID Type column does not match the format of the value you entered.

The fix depends on whether the barcode in your file or the one in Amazon's catalogue is correct. See our guide to error 8541 for the decision tree.

SKU-ASIN mismatch (error 8566)

Error 8566 means the SKU you submitted is already mapped to a different ASIN in your catalogue. Amazon treats the SKU-to-ASIN link as permanent within an account. You cannot reassign a SKU to a different ASIN by uploading a flat file with a new ASIN against the same SKU.

The fix is to either use the correct ASIN for that SKU, or delete the SKU mapping and recreate it. Full details in our guide to error 8566.

UPC-brand mismatch (error 8572)

Error 8572 fires when the brand name in your flat file does not match the brand associated with the product identifier (UPC or EAN) in Amazon's catalogue. This is an anti-counterfeiting check. If your brand name has a legitimate variation, such as an accent character or a "Ltd" suffix, you will need to either match the exact form Amazon expects or file a case to update it.

See our guide to error 8572 for the resolution path.

Brand registry issues (error 5665)

Error 5665 means Amazon cannot verify your brand ownership. This typically occurs when you try to list under a brand name that is enrolled in Amazon Brand Registry but your seller account is not authorised as a selling partner for that brand. It also fires when the brand name in your file does not exactly match the registered name, including capitalisation, spacing, and special characters.

The fix requires either an exact brand name match or authorisation from the brand owner through Brand Registry. See our guide to error 5665.

Character limit exceeded (error 90117)

Error 90117 fires when a field exceeds its maximum character or byte limit. The most common triggers are titles over the category limit, bullet points over 500 characters, and backend search terms over 250 bytes. Note the distinction: some limits are measured in characters, others in bytes. Characters with accents or special symbols use more than one byte each, so a 250-character string can exceed a 250-byte limit.

See our guide to error 90117 for the field-by-field limits.

Custom programme errors (AC codes)

AC-prefixed error codes relate to Amazon's custom programme, which handles product customisation options like engraving, monogramming, or personalised text. These errors appear when customisation fields are misconfigured, when the customisation data format does not match what the programme expects, or when customisation is enabled for a product type that does not support it.

These are niche but frustrating because the error messages are often opaque. See our guide to AC error codes for the full breakdown.

GTIN and barcode problems

A significant portion of flat file errors trace back to product identifiers. Amazon uses GTINs (which include UPCs, EANs, and ISBNs) as the backbone of its catalogue. When identifiers are wrong, mismatched, or duplicated, errors cascade.

• Wrong Product ID Type: If your barcode is an EAN-13 but the Product ID Type column says UPC, Amazon rejects it. EAN and UPC are different formats even though they look similar.
• Duplicate GTINs: Two different ASINs with the same GTIN will cause merge or rejection errors. This happens when sellers reuse barcodes across product variations.
• Exemption not applied: If your product qualifies for a GTIN exemption, you must apply for and receive the exemption in Seller Central before uploading without a barcode. Otherwise, every row without a GTIN fails.

How to debug a failed upload systematically

When a processing summary comes back with errors, resist the urge to fix one row at a time. A systematic approach saves hours.

1. Download the full processing summary. Do not rely on the preview in Seller Central, which sometimes truncates long error messages.
2. Sort by error code, not by SKU. Errors with the same code almost always share one root cause. Fixing that root cause once fixes every affected row.
3. Check your row count. Compare the number of rows in the processing summary against the number of data rows in your uploaded file. If any are missing, the file was corrupted during export or upload.
4. Verify your template version. Amazon periodically updates flat file templates. Uploading a file based on an old template version will produce errors for columns that have been renamed, moved, or removed.
5. Fix errors before warnings. Some warnings are caused by the same root issue as an error in another row. Fix the errors first, re-upload, then address any remaining warnings.
6. Re-upload only the failed rows. Create a new file containing only the corrected rows rather than re-uploading the entire file. This produces a cleaner processing summary and avoids accidentally overwriting values that processed correctly.

Common traps that are not obvious

Some flat file problems do not produce clear error messages. These are the ones that catch experienced sellers.

• The Listing Action column matters. "Edit (Partial Update)" only changes the fields you include. "Edit (Update)" expects every field to be populated and can blank out fields you left empty. Using the wrong action is one of the most common causes of data loss in flat file uploads.
• Product Type is required even on partial updates. Amazon uses it to determine which validation rules to apply. Without it, the row fails because Amazon cannot identify the correct attribute schema.
• Column positions shift between template versions. If you are copying data from an old template into a new one, check that the column headers align. Amazon has shifted columns by one position in recent template updates, which means data ends up in the wrong field.
• Excel auto-formatting corrupts values. Excel converts long numbers to scientific notation, strips leading zeros from barcodes, and reformats dates. Always check your exported file in a text editor before uploading.

Tools that help

Reading a processing summary manually is workable for small uploads, but anything over a few dozen rows benefits from tooling that can parse the tab-separated format and group errors for you.

Our guide to monitoring flat file errors covers how to track recurring patterns across multiple uploads. The listing issues scanner can catch many of these problems before you upload, by validating your file against Amazon's current rules.

For a broader overview of flat file error handling, see our introductory flat file errors guide, which covers the most frequently encountered errors with step-by-step fixes.