Overview

Sellers using Amazon’s bulk relationship feeds may encounter error 8018 when they try to delete a parent‑child link that does not exist in the catalog. The message appears during feed processing and can halt a batch of updates. Recognizing why the error occurs and how to address it prevents unnecessary resubmissions and keeps catalog‑management workflows running smoothly.

Key Points

• Error text — The feed returns “Cannot delete a non‑existing relationship for SKU [XYZ]”, where [XYZ] is the parent SKU you attempted to modify.
• Root cause — The delete instruction references a parent‑child pairing that Amazon cannot locate in its current product‑relationship database.
• Typical trigger — Bulk feeds that contain outdated SKU pairings, such as a child SKU that was already removed in a prior submission, generate the error most often.
• No fix required in many cases — If the relationship never existed, the error is informational only; the catalog already reflects the desired state.
• Impact on processing time — Although not a health‑risk, the error adds entries to the feed‑processing log, which can clutter reports for sellers handling large inventories.
• Prevention tip — Maintaining a fresh export of active relationships before issuing delete commands eliminates most occurrences.

How Product Relationship Feeds Work

1. Create or modify a feed file — Sellers compile a tab‑delimited or XML file that lists parent SKUs, child SKUs, and an action code (e.g., “delete”). For example, a row might read PARENT123\tCHILD456\tD.
2. Upload to Seller Central — The file is submitted through the “Relationships” feed type in the bulk upload interface or via the Marketplace Web Service (MWS) API.
3. Amazon parses each line — The system searches its internal relationship table for a match between the supplied parent and child SKUs.
4. Action execution — If a matching link exists, Amazon removes it and records a successful status. If no match is found, the system returns error 8018 for that line, leaving the rest of the feed untouched.