Error while processing the following file: <file name>. The file already exists on the media.

An error occurred while processing the specified file. Another file with the same name already exists, or a file is being copied to the same location twice.

Check the files in your project for duplicate file names. If there are two different files with the same name, rename one of the files. If a single file is being added to the same location twice, remove one instance of the file or change the target directory of one instance of the file.