diff --git a/cura/Settings/MachineManager.py b/cura/Settings/MachineManager.py
index 2e9a643be4..8a1be1d6d3 100755
--- a/cura/Settings/MachineManager.py
+++ b/cura/Settings/MachineManager.py
@@ -1016,27 +1016,35 @@ class MachineManager(QObject):
 
     def _setQualityChangesGroup(self, quality_changes_group):
         quality_type = quality_changes_group.quality_type
-        quality_group_dict = self._quality_manager.getQualityGroups(self._global_container_stack)
-        quality_group = quality_group_dict[quality_type]
+        # A custom quality can be created based on "not supported".
+        # In that case, do not set quality containers to empty.
+        if quality_type == "not_supported":
+            quality_group = None
+        else:
+            quality_group_dict = self._quality_manager.getQualityGroups(self._global_container_stack)
+            quality_group = quality_group_dict[quality_type]
 
         quality_changes_container = self._empty_quality_changes_container
-        quality_container = self._empty_quality_changes_container
         if quality_changes_group.node_for_global:
             quality_changes_container = quality_changes_group.node_for_global.getContainer()
-        if quality_group.node_for_global:
-            quality_container = quality_group.node_for_global.getContainer()
+        quality_container = self._empty_quality_changes_container
+        if quality_group is not None:
+            if quality_group.node_for_global:
+                quality_container = quality_group.node_for_global.getContainer()
 
         self._global_container_stack.quality = quality_container
         self._global_container_stack.qualityChanges = quality_changes_container
 
         for position, extruder in self._global_container_stack.extruders.items():
             quality_changes_node = quality_changes_group.nodes_for_extruders.get(position)
-            quality_node = quality_group.nodes_for_extruders.get(position)
+            quality_node = None
+            if quality_group is not None:
+                quality_node = quality_group.nodes_for_extruders.get(position)
 
             quality_changes_container = self._empty_quality_changes_container
-            quality_container = self._empty_quality_container
             if quality_changes_node:
                 quality_changes_container = quality_changes_node.getContainer()
+            quality_container = self._empty_quality_container
             if quality_node:
                 quality_container = quality_node.getContainer()