---
schema_version: "1"
id: b2863a280276c08ad009cfe88d84da5cc50c43c1d8aa4795852e59ce85c71570
title: Subscriber De-Duplication on Sends
collection: admin
version: current
locale: en-us
portal_url: https://docs.salesforce.com/admin/current/en-us/mktg/264-0-0/mc_es_deduplication.md
canonical_url: https://help.salesforce.com/s/articleView?id=mktg.mc_es_deduplication.htm&release=264.0.0&type=5
source_site: help.salesforce.com
content_type: documentation
content_hash: 049f4ef805a544aabed13ba1d79eddf8ec2332854d8059656ae2c3019a7533cd
description: De-duplication is a process Email Studio uses to remove duplicate instances of the same subscriber on a send. Our system does removal either automatically or requires configuration from the user, depending on the audience type used in the sent.
products:
  - Marketing
  - Marketing Cloud Engagement
release: "264"
---
# Subscriber De-Duplication on Sends

De-duplication is a process Email Studio uses to remove duplicate instances of the same subscriber on a send. Our system does removal either automatically or requires configuration from the user, depending on the audience type used in the sent.

Lists, groups, and data filters created from a list are always de-duplicated at the time of send by SubscriberID.

Data extensions are de-duplicated by email address. By checking the appropriate box, the system removes the duplicate email address from the send. If this option isn’t checked, the system tries to send an email for every row in targeted data extensions and data extension data filter. If a bounce occurs, we log a bounce for each send attempt to the duplicate email address.

![Note](https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-mktg-mc_email-264-0-0-production-enus/a0b807ef-dfbb-412c-b26e-310d91f2d6df/images/icon_note.png)

Note Triggered email sends don’t have a de-duplication mechanism.