Understand duplicate customer warnings in the migration log

Store Importer now writes warning-level entries to the migration job log when Shopify rejects a customer because their email address or phone number is already used by an existing Shopify customer.

The warnings appear as:

• Email has already been taken
• Phone has already been taken

Each warning includes the customer’s ID in the source store and their name, so you can identify the affected record.

What to do when you see a warning

Check Shopify for the customer named in the warning and confirm that the expected customer already exists. The warning means Shopify did not create that customer record during this job; it does not mean the entire migration failed.

When you re-import customers, warnings for most or even all of them can be normal because those customers may already be in Shopify from the earlier import.

Phone has already been taken can also appear during a first import. Shopify requires phone numbers to be unique across the entire shop, while Store Importer’s duplicate check only looks within the current migration job. A customer created outside that job may therefore already use the phone number.

What the migration log does not show

These warnings do not mean that every customer import failure is written to the migration log. Other Shopify customer errors, such as Email is invalid, are not currently shown there.