Materias: Fixed small bug in material editor

src/Mod/Material/MaterialEditor.py

@@ -96,7 +96,9 @@ class MaterialEditor(QtGui.QDialog):
         # look for cards in both resources dir and a Materials sub-folder in the user folder.
         # User cards with same name will override system cards
         paths = [FreeCAD.getResourceDir() + os.sep + "Mod" + os.sep + "Material" + os.sep + "StandardMaterial"]
-        paths.append(FreeCAD.ConfigGet("UserAppData") + os.sep + "Materials")
+        ap = FreeCAD.ConfigGet("UserAppData") + os.sep + "Materials"
+        if os.path.exists(ap):
+            paths.append(ap)
         self.cards = {}
         for p in paths:
             for f in os.listdir(p):