diff --git a/nilmtk_contrib/disaggregate/afhmm_sac.py b/nilmtk_contrib/disaggregate/afhmm_sac.py
index 237064b..56ea73e 100644
--- a/nilmtk_contrib/disaggregate/afhmm_sac.py
+++ b/nilmtk_contrib/disaggregate/afhmm_sac.py
@@ -256,7 +256,11 @@ def disaggregate_thread(self, test_mains,index,d):
                 prob = cvx.Problem(expression, constraints)
 
                 prob.solve(solver=cvx.SCS,verbose=False, warm_start=True)
-                s_ = [i.value for i in cvx_state_vectors]
+                s_ = [
+                    np.zeros((len(test_mains), self.default_num_states)) if i.value is None
+                    else i.value
+                    for i in cvx_state_vectors
+                ]
 
         prediction_dict = {}
         for appliance_id in range(self.num_appliances):
@@ -302,4 +306,4 @@ def disaggregate_chunk(self, test_mains_list):
             
         return predictions_lst
 
- 
\ No newline at end of file
+