I can't find a user who I'm searching for.

Users who have been invited must complete their registration to have an account.

This article applies to All editions

A common scenario a Centercode administrator experiences is attempting to search for a user account but not finding it. In most cases, this is because the user was invited but didn't access their invitation yet. To resolve this simple, you may send a follow-up email invitation.

Teams and Legacy edition users can check their Recruiting Management pages to see the status of a particular user invite.

Resources for that are below:

Managing Opportunity Pools
Recruiting FAQ