diff --git a/plugins/cas_auth_unl/migration.php b/plugins/cas_auth_unl/migration.php
index 541e58b21ad748463650a01aa8b13c1748b26946..a373a7e023b8a3dd63ac27ed90a2214c81a32652 100644
--- a/plugins/cas_auth_unl/migration.php
+++ b/plugins/cas_auth_unl/migration.php
@@ -60,9 +60,13 @@ foreach ($users as $source_user) {
             continue;
         }
         
-        $target_user = get_user($user_guid);
+        if (!$target_guid) {
+            continue;
+        }
+        
+        $target_user = get_user($target_guid);
     }
-    
+
     foreach ($icon_sizes as $size) {
         if (!$icon = @file_get_contents('http://planetred.unl.edu/pg/icon/'.$source_user['username'].'/'.$size, false, $context)) {
             //No icon was found, skip.