diff --git a/lib/Kolab/Utils/DAVBackend.php b/lib/Kolab/Utils/DAVBackend.php
--- a/lib/Kolab/Utils/DAVBackend.php
+++ b/lib/Kolab/Utils/DAVBackend.php
@@ -170,7 +170,7 @@
                     }
                     // restrict renaming to personal folders only
                     if ($folder->get_namespace() == 'personal') {
-                        $parts = preg_split('!(\s*/\s*|\s+[»:]\s+)!', $val);
+                        $parts = preg_split('!(*UTF8)(\s*/\s*|\s+[»:]\s+)!', $val);
                         $updates['oldname'] = $folder->name;
                         $updates['name'] = array_pop($parts);
                         $updates['parent'] = join('/', $parts);