Overview

Amazon sellers encounter error 99016 when a product feed includes more instances of a particular attribute than the catalog permits. The validation failure stops the creation or update of the affected listings until the excess entries are removed. Promptly fixing the issue keeps bulk‑upload schedules on track and prevents inventory delays.

Key Points

• Attribute caps are strict — Every catalog field has a defined maximum count; for example, the “size” attribute may allow only one entry per SKU, and adding a second triggers error 99016.
• Duplicate rows are the leading cause — Copy‑pasting rows or merging spreadsheets often repeats the same column header, causing the same attribute to appear multiple times in a single feed line.
• Error output pinpoints the culprit — The processing report lists the offending attribute, the allowed limit (e.g., 1), and the actual count found (e.g., 3), making it easy to locate the problem.
• Resubmission without changes won’t help — Uploading the original file again returns the same rejection; the feed must be edited to conform to the attribute limits before a new submission.
• Single‑value fields must stay single — Attributes such as “brand” or “manufacturer” accept only one value; attempting to list several values separated by commas will be flagged as excess occurrences.
• Category‑specific templates enforce rules — Using Amazon’s official flat‑file template for the product’s category automatically hides disallowed duplicate columns, reducing the chance of this error.
• Third‑party tools can introduce duplicates — Some listing software exports each attribute as a separate column per variation, which can unintentionally create multiple instances of a single‑value field.

How to Fix Error 99016

1. Open the processing report — After a failed upload, download the error report; it will highlight the attribute (e.g., “color”) and show “found 3, allowed 1.” For a SKU ABC123, the report might read: “Attribute color exceeds maximum occurrences.”