The optional overwrite parameter, which you can specify once only, indicates whether any existing files in the destination directory are overwritten when converting the user database. This is a simple restart feature at the complete file level.
The default value of false indicates that the contents of the destination directory are not overwritten. Specify this parameter with a value of true if you want to overwrite (replace) an existing map files in the destination directory if they are present in the source database that you are converting.