diff --git a/Config.txt b/Config.txt
index f337a5e..f5cb4f5 100644
--- a/Config.txt
+++ b/Config.txt
@@ -26,6 +26,7 @@
 14101 - User name doesn't match rules
 14102 - User ID not specified
 14103 - User name already exists
+14104 - User ID not existing
 
 = highscores.php =
 15101 - User ID not specified
diff --git a/Database.php b/Database.php
index cacaeee..e2af49c 100644
--- a/Database.php
+++ b/Database.php
@@ -73,9 +73,10 @@ class Database
             case 12103:
                 return 'Sorry, we only have '.$values[0].' questions. Please try again.';
             case 12104:
+            case 14104:
             case 15102:
             case 16102:
-                return 'The specified user name does not exist. This is an internal error.';
+                return 'The specified user ID does not exist. This is an internal error.';
             case 13102:
                 return 'No valid time specified. This is an internal error.';
             case 13103:
diff --git a/rename.php b/rename.php
index 4690125..5ce96c1 100644
--- a/rename.php
+++ b/rename.php
@@ -18,6 +18,9 @@ if(preg_match(PATTERN, $name) != 1) {
     $error = 14101;
 } else if($uid == '') {
     $error = 14102;
+} else if($db->query('SELECT EXISTS (SELECT 1 FROM "Users" WHERE "ID" = $1)', array($uid))
+    ['data'][0]['exists'] == 'f') {
+    $error = 14104;
 } else {
     $db->query('UPDATE "Users" SET "name" = $1 WHERE "ID" = $2', array($name, $uid));
     if(preg_match('/violates unique constraint "Users_name_unique"/', pg_last_error()) == 1) {