medusajs/medusa · error · MedusaError

Customer with this email already has an account

Error message

Customer with this email already has an account

What it means

Thrown when creating a customer account for an email that already belongs to a registered customer (has_account=true) and an authIdentityId is supplied — i.e. trying to attach a new auth identity to an already-registered email.

Source

Thrown at packages/core/core-flows/src/customer/steps/validate-customer-account-creation.ts:49

    const { email } = input.customerData

    if (!email) {
      throw new MedusaError(
        MedusaError.Types.INVALID_DATA,
        "Email is required to create a customer"
      )
    }

    // 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. Instead of creating, authenticate the existing customer and use the auth identity merge/link flow (e.g. linkAuthIdentity / existing account login)
2. Surface 'email already registered' to the client and prompt login
3. Guard by checking the customer by email before invoking the workflow

Example fix

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

// after: pre-check and direct to login/link
const [existing] = await customerService.listCustomers({ email })
if (existing?.has_account) {
  throw new MedusaError(MedusaError.Types.DUPLICATE_ERROR, "Please log in")
}
await createCustomerAccountWorkflow(container).run({ input: { customerData: { email }, authIdentityId } })

const [existing] = await customerService.listCustomers({ email })
if (existing?.has_account) return { alreadyRegistered: true }

try { await createCustomerAccountWorkflow(scope).run({ input }) } catch (e) { if (e.type === MedusaError.Types.DUPLICATE_ERROR) { /* prompt login / send to auth identity linking */ } throw e }

When it happens

Trigger: Calling createCustomerAccountWorkflow where the email already has has_account=true and input.authIdentityId is set (e.g. user registers a second auth provider on an email that is already registered).

Common situations: User signs up again with a different auth provider (Google vs email/password) using the same email; double-submit of the registration form; invitation/accept flows that call account creation for an existing account.

Related errors

• Guest customer with this email already exists
• 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/5b69ed6d6e0b2ab5. Report an issue: GitHub.