---
schema_version: "1"
id: 2f22c1bbda373b2d039f20c7b2ccc60a0b838baa9c3927349db14ce93a246e3a
title: List Detective
collection: admin
version: current
locale: en-us
portal_url: https://docs.salesforce.com/admin/current/en-us/mktg/264-0-0/mc_es_list_detective.md
canonical_url: https://help.salesforce.com/s/articleView?id=mktg.mc_es_list_detective.htm&release=264.0.0&type=5
source_site: help.salesforce.com
content_type: documentation
content_hash: bc41a3f00ced36e51788104ed0947b8b15d6eeb90efcf0ca380ad6227c029e7e
description: List Detective is a tool that maintains information on email addresses and domains that could cause deliverability problems for your email sends. This includes email addresses that are known spam traps (inactive addresses used by domains to identify spammers) and domains that no longer provide email services.
products:
  - Marketing
  - Marketing Cloud Engagement
release: "264"
---
# List Detective

List Detective is a tool that maintains information on email addresses and domains that could cause deliverability problems for your email sends. This includes email addresses that are known spam traps (inactive addresses used by domains to identify spammers) and domains that no longer provide email services.

List Detective automatically runs to help maintain deliverability for all clients. This app checks the following activities against List Detective and prevents the activity from executing if it includes problematic email addresses or domains:

- Import a subscriber list
- Send to a data extension
- Send a triggered email
- Web Collect
    
    ![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 Configure your Web Collect supporting page to display a friendly error description corresponding to error code 4.

![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 You can customize the List Detective settings for your account to exclude addresses or domains that you believe are active subscribers who have opted in to receive your communications. When a customize list detective is enabled and a rule is implemented that would exclude subscribers, existing subscribers in the All Subscribers list aren’t excluded from sends. Unsubscribe subscribers from the All Subscribers list before sending messages. Contact your account representative to request this customization.