Duplicate SKU Shopify: Diagnose Colliding Product Identifiers

The problem

Duplicate SKU values in a Shopify catalog silently break the systems that trust them. ERP syncs merge the wrong rows, inventory updates hit the wrong variant, and AI shopping feeds drop colliding products instead of guessing. Most stores only notice after an incident — a mispriced listing, an oversell, or a feed rejection that takes days to trace back to one repeated identifier.

Diagnostic checklist

• Export variants and group by SKU — any SKU appearing on more than one variant is a collision.
• Check parent products and their variants for copied SKUs from CSV imports.
• Look for blank or placeholder SKUs that later get reassigned to a live product.
• Review recent bulk imports for suffixes like -1, -copy, or _2 that hide the original collision.
• Confirm third-party apps are not minting SKUs outside your ERP or PIM of record.