Duplicate TeamCity email notifications: distribution list user added to 'All Users' group – Support | JetBrains

Symptoms

When a TeamCity user account representing an email distribution list is added to the built-in All Users group (or any other group with notification rules configured), every member of that group receives email notifications twice: once to the individual TeamCity account email, and once to the distribution list (which then fans the email back out to the same recipients).

Cause

Notification rules in TeamCity can be configured at two levels:

Per-user — each user account has individual notification rules under its profile.
Per-group — administrators configure notification rules on a user group, and they are applied uniformly to every member of that group.

The built-in All Users group automatically contains every TeamCity user. Any notification rule added to this group is delivered to every user, and there is no mechanism to exclude specific members from a group-level notification rule. When a distribution list user is in the same group, that user receives the same notification independently, and the mail server then delivers the message a second time to every recipient on the distribution list.

Resolution

To consolidate notifications onto a single distribution list user:

Remove the notification rules from the All Users group at Administration | Groups | All Users | Notification Rules.
Clear any per-user notification rules on the individual user accounts that should not be emailed directly at Administration | Users | <user> | Notification Rules.
Configure the notification rules on the distribution list user account only, as that user's own per-user rules at Administration | Users | <distribution list user> | Notification Rules.

The distribution list user becomes the only TeamCity notification recipient, and the mail server fans the email out to each address on the list.

When notifications are required for a subset of users (not everyone), create a dedicated user group containing only those users and configure the notification rules at the group level. Membership in a non-default group can be edited directly, unlike the All Users group.