medusajs/medusa · error · MedusaError

Guest customer with this email already exists

Error message

Guest customer with this email already exists

What it means

Thrown when a guest customer record with the same email already exists (has_account=false) and the request supplies no authIdentityId — the workflow cannot disambiguate creating another guest for the same email.

Source

Thrown at packages/core/core-flows/src/customer/steps/validate-customer-account-creation.ts:56

    }

    // Check if customer with email already exists
    const existingCustomers = await customerService.listCustomers({ email })

    if (existingCustomers?.length) {
      const hasExistingAccount = existingCustomers.some(
        (customer) => customer.has_account
      )

      if (hasExistingAccount && input.authIdentityId) {
        throw new MedusaError(
          MedusaError.Types.DUPLICATE_ERROR,
          "Customer with this email already has an account"
        )
      }

      if (!hasExistingAccount && !input.authIdentityId) {
        throw new MedusaError(
          MedusaError.Types.DUPLICATE_ERROR,
          "Guest customer with this email already exists"
        )
      }
    }
  }
)

View on GitHub (pinned to 5e06e544a2)

Solutions

1. Supply the authIdentityId (register through an auth provider flow) so the existing guest is upgraded/linked instead of duplicated
2. Delete or reuse the existing guest customer before retrying
3. Handle DUPLICATE_ERROR and prompt the user to log in or reset

Example fix

// before
await createCustomerAccountWorkflow(container).run({
  input: { customerData: { email } }, // no authIdentityId
})

// after
await createCustomerAccountWorkflow(container).run({
  input: { customerData: { email }, authIdentityId },
})

const [existing] = await customerService.listCustomers({ email })
if (existing && !existing.has_account && !authIdentityId) {
  // reuse/upgrade the existing guest instead of creating another
}

try { await createCustomerAccountWorkflow(scope).run({ input }) } catch (e) { if (e.type === MedusaError.Types.DUPLICATE_ERROR && /Guest/.test(e.message)) { /* attach authIdentityId or reuse guest */ } throw e }

When it happens

Trigger: Calling createCustomerAccountWorkflow without authIdentityId when a guest customer with the same email was previously created (e.g. abandoned guest checkout).

Common situations: Guest checkout performed earlier with the same email, then account creation attempted without an auth identity; tests creating guest customers repeatedly with the same email fixture.

Related errors

• Customer with this email already has an account
• Email is required to create a customer
• Invalid step input
• Invalid step input
• Auth identity not found

AI-assisted analysis of medusajs/medusa@5e06e544a2 (2026-08-27). Data as JSON: /api/errors/6ece2d26ea01a76f. Report an issue: GitHub.