The "Map object names automatically" option can be turned off from the "Name Mapping Options" dialog. See the "Name Mapping Options Dialog" help topic for more information. However, if a name mapping scheme is already created, TestComplete will use mapped names for the objects over which actions are performed during the recording. In this case, you need to delete the scheme: you can either clear the contents of the Mapped Objects and Aliases panes from the Name Mapping editor or just delete the NameMapping project item.
Could you please explain exactly what problem makes you want to disable this feature?