CP Catalog Preflight

SHOPIFY PRODUCT CSV / VARIANT UPDATES

Changing SKUs by CSV? Keep the option columns in view.

A CSV can be well formed and still be risky for a variant update. Shopify warns that when variant-related columns such as SKU are updated, their corresponding Option1 name and Option1 value data must also be included. If those option columns are omitted, Shopify says a new default variant can be created and existing variants deleted. This worksheet helps you check the dependency before an import—not after one.

Before any bulk update: export a current backup, keep the original untouched, and test a small representative import. Neither this article nor Catalog Preflight can predict all changes inside your store.

The mistake to look for

Suppose a fictional shirt has Size variants M and L. You export products, edit only the SKU values, and reduce the CSV to URL handle,Title,SKU. Those identifiers look reasonable, but the file no longer says which option value belongs to which SKU. Shopify's documented dependency calls for the option columns alongside variant-related fields. Even if your spreadsheet displays neat rows, check the actual exported CSV headers and values before uploading.

A small, fictional comparison

The following is an illustration using current header names, not a Shopify export from a real shop and not an import guarantee. The left example deliberately omits the option relationship; the right retains it.

Review before importing

URL handle,Title,SKU
linen-shirt,Linen Shirt,LINEN-M
linen-shirt,Linen Shirt,LINEN-L

The two SKU rows have no Size values. Do not infer that Shopify will map them to the existing variants.

Keep the variant context

URL handle,Title,Option1 name,Option1 value,SKU
linen-shirt,Linen Shirt,Size,M,LINEN-M
linen-shirt,Linen Shirt,Size,L,LINEN-L

Each SKU remains beside its option value. Compare these rows against a fresh export before using them; other columns and store state can matter.

A five-minute pre-import worksheet

  1. Confirm intent. Are you creating new products or updating existing ones? Shopify requires URL handle and Title for product updates; for new products it requires Title, and URL handle when adding variants.
  2. Inventory variant fields. If the update touches SKU, weight or another variant-related column, retain the corresponding option-name and option-value columns from the export. Verify each edited row still identifies its intended variant.
  3. Check the bytes, not only the spreadsheet view. Export UTF-8 comma-separated CSV. Look for duplicate/blank headers, stray quotes, and shifted row widths. A comma inside a product field needs proper CSV quoting.
  4. Compare against the backup. Count variants for two or three representative handles and compare option combinations. Look for two rows with the same handle and option values; Shopify lists non-unique options as a possible import error.
  5. Test, inspect, then scale. Import a small representative subset using Shopify's own workflow and inspect the products and variants in the store. If the result differs, stop and restore from your backup instead of uploading the bulk file.

Where the free and paid checks fit

Try the limited browser checker with fictional or nonsensitive product data. It checks selected structural issues and option-column dependencies; it does not access your shop or test an actual import. The €5.90 offline Catalog Preflight download adds selected value/URL/duplicate-SKU/spreadsheet-risk checks, line-numbered CSV and JSON findings, and EN/FI interface controls. It does not automatically repair a file, guarantee Shopify acceptance, or compare it with live variants. Rule explanations are in English.

Read Shopify's guidance before you upload

Shopify's product CSV reference documents required columns and the option dependency, including the warning about creating a default variant and deleting existing variants. Its common import issues page discusses duplicate options, missing product data, illegal quoting, and image URL problems. Those official pages, not this checker, are the authority for the import format.

Independent educational material · Updated 19 October 2026 · Examples are fictional · Not affiliated with Shopify.