Changing Admin user in Alfresco 3.2 +...

...when you have no other administrator.

This is one of the ways to change Alfresco administrator, but there are another using groups.

Locate tomcat/shared/classes/alfresco/alfresco-global.properties

Add this property:

alfresco_user_store.adminusername=admin

And replace admin identifier by other user identifier.

Reboot Alfresco and login with new "admin" user.