Learn why directory user emails must be unique among active users, and how to avoid conflicts.
Directory Sync requires directory user emails to be unique among active users within a directory. If an identity provider tries to provision or update a directory user with an email that another active user in the same directory already has, that request is declined and the affected user won’t sync until the conflict is resolved. This is scoped per directory; the same email can still exist in different directories.
Only active users count toward uniqueness. Deactivating a duplicate record in the identity provider immediately frees its email for the active user that should hold it.
Unique emails make user resolution predictable. When each active user in a directory has a distinct email, AuthKit, just-in-time provisioning, and your own application can reliably resolve a person by their email address. This keeps downstream authentication and account-linking behavior consistent for your users.
Email conflicts originate in your customers’ identity providers, so the fixes are IT admin actions. Share this guidance with the affected admins to keep directories syncing cleanly.