Recently we had a fairly large customer base we had to import from an ePages shop into Magento. During import with dataflow profiles, using some test data, we found that all email addresses of the test data received a newsletter subscription success email (we imported clients with column is_subscribed set to 1). Sending tens of thousands of newsletter succes mails was not what we wanted, so here’s a pragmatic way to turn that off for the initial import only:

Open file app/code/core/Mage/Newsletter/model/Subscriber.php. Disable the line containing “sendConfirmationSuccessEmail() in the function called “subscribeCustomer()”). Now, your customers will not receive newsletter confirmation emails on importing.

Background: the dataflow customer import saves customer data using a regular save action on the customer object. The newsletter module of Magento listens for a customer save event and fires the subscribeCustomer() function when that happens. Of course, enable the line you edited in the subscribeCustomer() function again after you’re done!