diff --git a/classes/File.php b/classes/File.php
index 189e04ce02..79a7d66813 100644
--- a/classes/File.php
+++ b/classes/File.php
@@ -169,7 +169,11 @@ class File extends Memcached_DataObject
     {
         require_once 'MIME/Type/Extension.php';
         $mte = new MIME_Type_Extension();
-        $ext = $mte->getExtension($mimetype);
+        try {
+            $ext = $mte->getExtension($mimetype);
+        } catch ( Exception $e) {
+            $ext = strtolower(preg_replace('/\W/', '', $mimetype));
+        }
         $nickname = $profile->nickname;
         $datestamp = strftime('%Y%m%dT%H%M%S', time());
         $random = strtolower(common_confirmation_code(32));