existing Argument
The optional existing argument specifies whether the destination folder specified in the defaultPath argument contains an existing database. (An error can occur if the control file on the destination database does not match the control file on the source system.)
If the destination folder does not contain an existing database, specify this argument with a value of false, to create a _control.dat file. The default value of true indicates that the _control.dat file already exists in the target database.