diff --git a/addon/appModules/splstudio/__init__.py b/addon/appModules/splstudio/__init__.py
index 40ef45b97..d5d325da4 100644
--- a/addon/appModules/splstudio/__init__.py
+++ b/addon/appModules/splstudio/__init__.py
@@ -1194,7 +1194,7 @@ def terminate(self):
 		self.carts.clear()
 		self._cachedStatusObjs.clear()
 		# Don't forget to reset timestamps for cart files.
-		splmisc._cartEditTimestamps = None
+		splmisc._cartEditTimestamps = []
 		# Just to make sure:
 		if splbase._SPLWin:
 			splbase._SPLWin = None
@@ -1609,7 +1609,7 @@ def script_toggleCartExplorer(self, gesture):
 			self.cartExplorer = False
 			self.cartsBuilder(build=False)
 			self.carts.clear()
-			splmisc._cartEditTimestamps = None
+			splmisc._cartEditTimestamps = []
 			# Translators: Presented when cart explorer is off.
 			ui.message(_("Exiting cart explorer"))
 
diff --git a/addon/appModules/splstudio/splmisc.py b/addon/appModules/splstudio/splmisc.py
index b98405a92..6bcd314a0 100755
--- a/addon/appModules/splstudio/splmisc.py
+++ b/addon/appModules/splstudio/splmisc.py
@@ -306,7 +306,7 @@ def _populateCarts(carts, cartlst, modifier, standardEdition=False, refresh=Fals
 
 
 # Cart file timestamps.
-_cartEditTimestamps = None
+_cartEditTimestamps = []
 
 
 # Initialize Cart Explorer i.e. fetch carts.