The CSV list sync option automatically deletes contacts from your account that aren't on the latest import file.

This is in contrast with the default import behaviour that only adds contacts to your database.

The CSV list sync option is only available for admin level users. It is not available on the Standard billing plan.

This option is enabled by request only. Please start a support chat to request it to be turned on for your account.

Click the "Show advanced settings" link near the bottom of the import settings page.

Check the related checkbox and adjust settings.

You can specify the maximum number of contacts to be deleted during the import process. This safeguards against unintended deletion of a large number of contacts. If the number of contacts to be deleted is more than the specified maximum then no contacts will be deleted.

Don't delete contacts with a specific tag: Any contact that matches this tag will not be deleted.

Contacts that match the email address associated with a user login to your account will not be deleted.

Contacts deleted by using this option aren't recoverable - there is no undo option.

The import confirmation email shows how many contacts were deleted as part of the CSV sync process or if no contacts were deleted because the contacts to be deleted were over the maximum limit. The import confirmation email is sent to the email address associated with your user login.

Syncing your contact list can also be automated using the daily automated CSV sync option.