diff --git a/CuraEngineBackend.py b/CuraEngineBackend.py
index 491b4fbd67..f9bb46ce9c 100644
--- a/CuraEngineBackend.py
+++ b/CuraEngineBackend.py
@@ -120,6 +120,7 @@ class CuraEngineBackend(Backend):
             return #No point in slicing an empty build plate
 
         self._slicing = True
+        self.processingProgress.emit(0.0)
 
         self._sendSettings()