If you create a new directory element, you cannot use the same name as an existing view-private file or directory, and you cannot use mkelem to convert an existing view-private directory structure into directory and file elements. To accomplish this task, use the clearfsimport and clearimport utilities.
Also, if you are adding a large number of files and directories to source control, use the clearfsimport command (or clearexport command) and clearimport command.
For more information, see the clearfsimport and clearimport reference pages in the IBM Rational ClearCase Command Reference.