The number of contacts or companies in a Teamleader segment might differ slightly from the segment in MailChimp. This due to the criteria that MailChimp maintains:

More contacts in Teamleader than in Mailchimp

  • Only contacts or companies that have an email address will be synchronised. Contacts or companies without an email address will not appear in MailChimp.
  • The email address is a unique key. If an email address appears multiple times in Teamleader, it will only be used once by MailChimp. Even if an email address is the same for the company as well as the related contact, you will only find it at the company in MailChimp.
  • People always have the option to unsubscribe from your emails. These people will be removed from the MailChimp segment, but will remain in Teamleader.
  • The same rule applies for so called ‘bounced’ email addresses. If an email address cannot be reached (this can be because of different reasons), it will be removed from the segment in MailChimp, but it will stay in Teamleader.
  • Bounced emails are managed by MailChimp, Teamleader only takes over the message. Want to know why an email bounced? Take a look at your MailChimp account
  • MailChimp limits the number of “Groups” to 60. This means that only 60 Teamleader segments can be synchronized. If you have more, check off the “synchronize to MailChimp” checkbox when creating/editing your segments.

More contacts in Mailchimp than in Teamleader

The number of contacts or companies can also be higher in MailChimp than in Teamleader. This is probably because you have a custom field that allows you to add multiple email addresses to one contact. Because an email address is a unique key in MailChimp, the segment will have a higher number than your Teamleader segment.


  • If you delete an entry in Mailchimp and not in Teamleader, Teamleader will create this contact again via the next sync.
  • If you delete an entry in Teamleader and not in Mailchimp, Teamleader will delete this contact in Mailchimp during the next sync.