diff --git a/erpnext/projects/doctype/task/task.py b/erpnext/projects/doctype/task/task.py
index e58bb79..5589684 100755
--- a/erpnext/projects/doctype/task/task.py
+++ b/erpnext/projects/doctype/task/task.py
@@ -166,7 +166,7 @@
 		self.update_nsm_model()
 
 	def update_status(self):
-		if self.status not in ('Cancelled', 'Completed'):
+		if self.status not in ('Cancelled', 'Completed') and self.exp_end_date:
 			from datetime import datetime
 			if self.exp_end_date < datetime.now().date():
 				self.date = 'Overdue'