Overview

Amazon reports error 99017 when a bulk upload contains contradictory values for the same product attribute in a single row. The conflict appears during feed validation, blocking the affected listings from being created or updated. Sellers must resolve the mismatch quickly to keep inventory visible and avoid sales interruptions.

Key Points

• Error text — The message reads “Values assigned to [attribute] conflict with each other,” inserting the specific attribute that triggered the issue.
• Root cause — Two or more columns in the submitted file try to set different values for the identical attribute, leaving Amazon’s system unable to decide which one to keep.
• Typical sources — Using both a generic column (e.g., Size) and a specialized column (e.g., Shirt_Size) with different entries, or filling out redundant variation‑theme fields that disagree.
• Template pitfalls — Updated category templates often add new columns that overlap with older ones, causing hidden conflicts when sellers reuse previous files.
• Resolution path — Identify the rows flagged, locate every column that maps to the disputed attribute, keep the correct value, and clear the others before resubmitting.

How Error 99017 Occurs

1. Feed upload — You submit a flat‑file or API feed through Seller Central; Amazon’s catalog engine scans every row for internal consistency.
2. Attribute mapping check — The system matches each column header to a catalog attribute; if multiple headers resolve to the same attribute, it compares the supplied values.
3. Conflict detection — When the values differ, the engine flags the row with error 99017 and returns a message that includes the attribute name.

Concrete examples for each step

1. Feed upload — A seller uploads a CSV containing 5,000 shoes using the “Clothing & Shoes” template.
2. Attribute mapping check — The file includes both “size” and “shoe_size” columns; Amazon maps both to the internal “Size” attribute.