Overview

Error 99018 appears when Amazon rejects a product feed because one or more attribute values do not meet the platform’s exact standards. The validation stops the entire file from processing, delaying new listings, price changes, or inventory updates. Sellers must correct the offending fields and resend the feed to keep their catalog current.

Key Points

• Attribute‑value mismatch — Supplying a value that is not on Amazon’s predefined list (e.g., “Reddish” for a color field that only accepts “Red”, “Blue”, “Green”) triggers error 99018.
• Formatting violations — Even a correct word can be rejected if it contains illegal characters, wrong case, extra spaces, or an unsupported encoding such as UTF‑16 instead of UTF‑8.
• Error report pinpoints the field — The processing summary returns the exact attribute name and the rejected entry, allowing sellers to locate the problem without scanning the whole file.
• Whole‑file resubmission required — After fixing the value, Amazon does not accept a partial update; the entire feed must be uploaded again for the changes to take effect.
• Bulk uploads are most vulnerable — Large flat‑file submissions increase the chance of typos or copy‑paste artifacts, especially when data is migrated from other marketplaces or generated by third‑party tools.

How to Resolve Error 99018

1. Download the processing summary — Open the Feed Processing Report in Seller Central; locate the row marked with error 99018, which lists the attribute (e.g., color) and the exact value that failed (e.g., Reddish).
2. Consult Amazon’s attribute guide — Navigate to the “Category‑specific product data” page for the relevant marketplace, find the allowed values for the flagged attribute, and note the required spelling, case, and punctuation. For example, the guide may specify that color accepts only “Red”, “Blue”, “Green”, and “Black”.
3. Correct the value in the feed file — Open the original flat file, replace the rejected entry with the exact accepted term, remove any leading/trailing spaces, and ensure the cell uses UTF‑8 encoding. If the attribute is a dropdown list, copy the value directly from Amazon’s reference list to avoid subtle differences.