Overview

Error 18200 appears when Amazon’s validation engine finds a mismatch between the attribute data you submit and the information stored in the catalog. The issue can surface during a new listing upload or when you modify an existing offer, and it typically blocks the affected SKU until the inconsistency is resolved. Sellers must address it promptly to avoid delays in getting products live and to keep bulk‑upload workflows running smoothly.

Key Points

• Attribute mismatch flagged — The error triggers when a submitted attribute value (e.g., “Material”) does not align with the value Amazon already has for that ASIN.
• Required field omitted — Leaving a mandatory column blank in a flat‑file or skipping a required XML element will also generate Error 18200.
• Applies to flat files and XML feeds — Both spreadsheet‑based inventory templates and programmatic XML submissions are subject to the same validation rules.
• Error message names the attribute — Amazon includes the exact attribute (such as “Size” or “Color”) in the error text, giving you a clear starting point for troubleshooting.
• Not a policy violation — The error is purely a data‑quality issue; it does not affect account health but can stall listings.
• Batch size influences detection speed — Smaller upload batches make it easier to isolate the offending SKU compared with a massive file that contains dozens of errors.

How Error 18200 Occurs

1. Data submission reaches Amazon’s validation layer — When you upload a flat‑file for the “Home & Kitchen” category, Amazon reads each row and checks every column against the category’s schema. Example: You submit a row for a stainless‑steel skillet with the “Finish” column left empty.
2. System cross‑references existing catalog data — If the ASIN already exists, Amazon compares your values with the stored attributes. Example: The catalog lists “Finish = Polished,” but your file says “Finish = Matte,” creating a conflict.
3. — The validation engine flags the discrepancy and returns Error 18200, citing the specific attribute (“Finish”) that caused the failure. : The response file shows “Error 18200 – Finish attribute inconsistent.”