--- a/svghmi/ui.py	Thu Jun 10 13:47:58 2021 +0200
+++ b/svghmi/ui.py	Thu Jun 10 14:05:44 2021 +0200
@@ -163,7 +163,7 @@
         self.root = self.AddRoot(root_display_name)
         self.SetPyData(self.root, None)
 
-        if lib_dir is not None:
+        if lib_dir is not None and os.path.exists(lib_dir):
             self._recurseTree(lib_dir, self.root, [])
             self.Expand(self.root)