diff --git a/blivetgui/blivet_utils.py b/blivetgui/blivet_utils.py
index e2f0a089..f7682414 100644
--- a/blivetgui/blivet_utils.py
+++ b/blivetgui/blivet_utils.py
@@ -1209,6 +1209,8 @@ def _create_snapshot(self, user_input):
                                            parents=[origin_lv.pool],
                                            origin=origin_lv,
                                            seg_type="thin")
+        else:
+            raise ValueError("Creating snapshots is not supported for %s" % user_input.device_type)
 
         actions.append(blivet.deviceaction.ActionCreateDevice(new_snap))
 
diff --git a/blivetgui/list_devices.py b/blivetgui/list_devices.py
index 2fd4a795..379f3947 100644
--- a/blivetgui/list_devices.py
+++ b/blivetgui/list_devices.py
@@ -125,6 +125,8 @@ def update_devices_view(self):
         model, treeiter = selection.get_selected()
         if treeiter and model:
             selected_device = model[treeiter][0].name
+        else:
+            selected_device = None
 
         # reload devices
         # adding new devices into TreeStore causing "changed" signal being