PHP Download Script Creates Unreadable ZIP File on Mac

Question

For reference, I have already read and tried the answers in these and several other threads:

Creating and serving zipped files with php

Opening downloaded zi

Answer 1

Here is what works

$zipName = 'myfile.zip';
$zipPath = 'mydirectory/' . $zipName;

    if (file_exists($zipPath)) {

        header("Pragma: public");
        header("Expires: 0");
        header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
        header("Cache-Control: public");
        header("Content-Description: File Transfer");
        header("Content-type: application/octet-stream");
        header("Content-Disposition: attachment; filename=\"".$zipName."\"");
        header("Content-Transfer-Encoding: binary");
        header("Content-Length: ".filesize($zipPath));
        ob_end_flush();
        @readfile($zipPath);
}