Do you wish to overwrite?

Why does ArcGIS say:

"The object named ".........shp" already exists. Do you wish to replace it?"

and then refuse to overwrite the feature? This, coupled with my other question, seems to mean I have to constantly create and delete temporary features so I can copy the linework into the final attributed table.

Is there some documentation that advises on data management? So far it seems quite inefficient.