diff --git a/plugins/CuraEngineBackend/StartSliceJob.py b/plugins/CuraEngineBackend/StartSliceJob.py
index b88a4a33d2..8ce3110a93 100644
--- a/plugins/CuraEngineBackend/StartSliceJob.py
+++ b/plugins/CuraEngineBackend/StartSliceJob.py
@@ -256,10 +256,7 @@ class StartSliceJob(Job):
             self._buildGlobalInheritsStackMessage(stack)
 
             # Build messages for extruder stacks
-            # Send the extruder settings in the order of extruder positions. Somehow, if you send e.g. extruder 3 first,
-            # then CuraEngine can slice with the wrong settings. This I think should be fixed in CuraEngine as well.
-            extruder_stack_list = sorted(list(global_stack.extruders.items()), key = lambda item: int(item[0]))
-            for _, extruder_stack in extruder_stack_list:
+            for extruder_stack in global_stack.extruderList:
                 self._buildExtruderMessage(extruder_stack)
 
             for group in filtered_object_groups:
diff --git a/plugins/UFPReader/__init__.py b/plugins/UFPReader/__init__.py
index 8f405d4f66..cfea4b9882 100644
--- a/plugins/UFPReader/__init__.py
+++ b/plugins/UFPReader/__init__.py
@@ -1,10 +1,15 @@
 #Copyright (c) 2019 Ultimaker B.V.
 #Cura is released under the terms of the LGPLv3 or higher.
 
+import sys
+
+from UM.Logger import Logger
+try:
+    from . import UFPReader
+except ImportError:
+    Logger.log("w", "Could not import UFPReader; libCharon may be missing")
+
 from UM.i18n import i18nCatalog
-
-from . import UFPReader
-
 i18n_catalog = i18nCatalog("cura")
 
 
@@ -21,6 +26,9 @@ def getMetaData():
 
 
 def register(app):
+    if "UFPReader.UFPReader" not in sys.modules:
+        return {}
+
     app.addNonSliceableExtension(".ufp")
     return {"mesh_reader": UFPReader.UFPReader()}