Bounce and List Deletion Warning
If you still wish to proceed, MailChimp will slowly send to the list over a period of hours to monitor the bounce and complaint rates. If the rates remain low, we'll complete sending to the remainder of the recipients. All existing addresses previously sent to through the account, and any addresses collected through our double opt-in process will be sent first.
Please be aware that the new list will be automatically deleted if bounce or complaint rates exceed thresholds. Only the newly imported addresses will be deleted. Any email addresses in the list that you have previously sent to through the account, and any addresses collected through our double opt-in process, will not be removed; you can continue to send to them as usual.
Noting this, we recommend you back up the list data before sending, as outlined in the following guide: How can I view or export my list?
I understand that if my campaign exceeds industry abuse thresholds, MailChimp will delete the list data as described.