$re = '/\.com\\\\([^\\\\]+)\\\\.*/';
$str = 'SERVERNAME2018-03-08 18:40:28 File: "x:\\_default\\app.address.com\\MedSoftware\\.data\\BackEnd.com\\Technical.Dictionaries.Service-180308182311\\Web.config", Name: "dictionaries_data_product", CS: "###connectionStrings.dictionariesdataproduct.connectionString" info: Format of the initialization string does not conform to specification starting at index 0. 6069
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php