diff --git a/qtgui/instrument.py b/qtgui/instrument.py
index 8ca94c4..c298e7b 100644
--- a/qtgui/instrument.py
+++ b/qtgui/instrument.py
@@ -309,8 +309,9 @@ class InstrumentTreeController(object):
 
     def react_instrumentStatusChanged(self, instrumentStatus:dict):
         self.parentMainWindow.qtApp.restoreOverrideCursor() #Sometimes the instrument was loaded with a cursor animation
-        gi = self.guiInstruments[instrumentStatus["idKey"]]
-        gi.updateStatus(instrumentStatus)
+        if instrumentStatus["idKey"] in self.guiInstruments:
+            gi = self.guiInstruments[instrumentStatus["idKey"]]
+            gi.updateStatus(instrumentStatus)
         self._adjustColumnSize()
 
         #We also cache the last status, as we cache the initial data. This way we can delete and recreate TreeItems without requesting new status data from the engine
@@ -327,8 +328,9 @@ class InstrumentTreeController(object):
 
     def react_instrumentMidiNoteOnActivity(self, idKey:tuple, pitch:int, velocity:int):
         #First figure out which instrument has activity
-        gi = self.guiInstruments[idKey]
-        gi.activity() #We only do a quick flash here. No need for velocity, pitch or note-off
+        if idKey in self.guiInstruments:
+            gi = self.guiInstruments[idKey]
+            gi.activity() #We only do a quick flash here. No need for velocity, pitch or note-off
 
 
     def contextMenu(self, qpoint): #strange that this is not an event but a qpoint