Only the administrator of the account can enable unsorted. To do this, go to the "Leads" - "Gear" and include incoming lead.For other users, the administrator can enable access to the unsorted in Settings - Users, by clicking the "incoming leads" button.
The functional is visible to users who have the right at least to create leads, contacts and companies.
If you do not have at least one of these rights - the user does not see the unsorted block.
Disabling unassembled simply hides it from the interface, but the functionality itself works, applications come.