diff --git a/lib/php/Converter.php b/lib/php/Converter.php
index 0b291dd..eb7df60 100644
--- a/lib/php/Converter.php
+++ b/lib/php/Converter.php
@@ -1367,14 +1367,21 @@ public function convertMemory($capacity)
             switch (strtolower($matches[3])) {
                 case 'pb':
                     $real_value *= 1024;
+                    //no break, continue to next
                 case 'tb':
                     $real_value *= 1024;
+                    //no break, continue to next
                 case 'gb':
                     $real_value *= 1024;
+                    //no break, continue to next
                 case 'mb':
                     $real_value *= 1024;
+                    //no break, continue to next
                 case 'kb':
                     $real_value *= 1024;
+                    break;
+                default:
+                    return null;
             }
 
             //then return as Mb.