diff --git a/examples/ELASTIC_T/BORN_MATRIX/Argon/Analytical/compute_born.py b/examples/ELASTIC_T/BORN_MATRIX/Argon/Analytical/compute_born.py
index 0f3265faeb..88cc8dcca2 100644
--- a/examples/ELASTIC_T/BORN_MATRIX/Argon/Analytical/compute_born.py
+++ b/examples/ELASTIC_T/BORN_MATRIX/Argon/Analytical/compute_born.py
@@ -1,7 +1,6 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
-import sys
 import numpy as np
 
 def reduce_Born(Cf):
diff --git a/examples/ELASTIC_T/BORN_MATRIX/Argon/Numdiff/compute_born.py b/examples/ELASTIC_T/BORN_MATRIX/Argon/Numdiff/compute_born.py
index 0f3265faeb..88cc8dcca2 100644
--- a/examples/ELASTIC_T/BORN_MATRIX/Argon/Numdiff/compute_born.py
+++ b/examples/ELASTIC_T/BORN_MATRIX/Argon/Numdiff/compute_born.py
@@ -1,7 +1,6 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
-import sys
 import numpy as np
 
 def reduce_Born(Cf):
diff --git a/examples/mdi/aimd_driver.py b/examples/mdi/aimd_driver.py
index 2d8fe10c1a..ee493ea31e 100644
--- a/examples/mdi/aimd_driver.py
+++ b/examples/mdi/aimd_driver.py
@@ -26,7 +26,7 @@
 #   -nsteps 5
 #     number of timesteps, default = 5
 
-import sys,math,random
+import sys
 import mdi
 import numpy as np
 from mpi4py import MPI
@@ -42,10 +42,9 @@ def error(txt=None):
 def perform_aimd(world,mm_comm,qm_comm):
 
   me = world.Get_rank()
-  nprocs = world.Get_size()
 
   # receive number of atoms from the MM engine
-  
+
   mdi.MDI_Send_command("<NATOMS",mm_comm)
   natoms = mdi.MDI_Recv(1,mdi.MDI_INT,mm_comm)
   natoms = world.bcast(natoms,root=0)
diff --git a/lib/install_helpers.py b/lib/install_helpers.py
index 7990463736..e1ebd1cde7 100644
--- a/lib/install_helpers.py
+++ b/lib/install_helpers.py
@@ -1,4 +1,4 @@
-import hashlib,os,subprocess,sys
+import hashlib,os,subprocess
 
 # try to auto-detect the maximum number of available CPUs
 def get_cpus():