I have a user that is unable to search (sidebar) on an auto-number field on a custom object. The field does have a master-detail relationship with an account, however this user has read all access to both accounts and the custom object. I checked the field level security and everyone in our organization has read access to the field.
When I search on the auto-number field I get results back. When he searches on the auto-number field he can't see the record.
What's getting in the way of that record being returned in search results?