If you have multiple customers in your Intercom workspace with the same email address, it may be because you’re passing a different user_ID for each one. Additionally, Intercom may associate incoming communications with the most recently updated user profile if multiple profiles use the same email address. To avoid confusion, ensure that each user is uniquely identified by a consistent and unique user ID.

When you define both an email address and user_ID for a user, Intercom uses the user_ID as a unique identifier. Intercom may also use cookie-based identification to merge profiles without emails, which helps unify Visitor/Lead and User profiles automatically based on device behavior. Avoid changing user_id for an existing email, as this creates a new User profile and can lead to duplicates.

In Intercom, a User is an identified contact with a user_id set, and a Lead is an unidentified contact — such as a site visitor who hasn't yet logged in.

A common cause of duplicate user profiles during CSV (comma-separated values) imports occurs when an existing user profile has no user_id set, but the CSV being imported includes both an email and a user_id. Because Intercom identifies contacts in order — Intercom ID, then user_id, then email — it will not fall back to matching on email if a user_id is present in the import. Instead, it creates a new contact, resulting in a duplicate. When importing data via CSV, ensure the Lead's email matches the User's email. Intercom will automatically merge the new Lead into the existing User profile. If the Lead already exists, manual merging is required.

To prevent duplicate user profiles during CSV imports, ensure user_id values are consistent and set for all users before running a CSV import. Use the API to update user_id for any existing users missing one.

For example, if you have two users, both with the email address test@example.com, but they have different user_IDs, Intercom will recognize these customers as two unique users.

To see which users have a user_id set, go to Contacts > People > All users and apply the filter User ID has any value. The filtered view shows each user's user_id, as in the example below:

It's currently not possible to merge two Users in Intercom. You can merge a lead into a user, but you cannot merge two users. When merging a Lead into a User, any data associated with the Lead is attributed to the User, and the Lead profile itself is deleted.

Once merged, the Lead profile is permanently deleted. The User profile retains all conversation history and data previously associated with the Lead.

You could clean up the users you don't want to keep by archiving them. You'd first have to figure out which of the two records you want to keep, though. There are two ways you could do this:

1. Using our Rest API

You'd want to create a script which would:

2. Using our CSV Export

The other option is to export your contacts as a CSV. Once exported, use a spreadsheet formula such as COUNTIF in Google Sheets or Excel to identify rows with duplicate email addresses. Alternatively, use a deduplication add-on from the Google Workspace Marketplace.

Archived users are hidden from your Contacts list but are not permanently deleted. You can unarchive them at any time from Contacts > People > All users by removing the archived filter.

To reduce duplicate user profiles in your Intercom workspace over time, follow these best practices:

Read the whole thread and find out how to clean up duplicates, here in Intercom Community.