diff --git a/run_nerf.py b/run_nerf.py
index bc270be86..57fbc79a8 100644
--- a/run_nerf.py
+++ b/run_nerf.py
@@ -791,12 +791,14 @@ def train():
         # Rest is logging
         if i%args.i_weights==0:
             path = os.path.join(basedir, expname, '{:06d}.tar'.format(i))
-            torch.save({
+            ckpt = {
                 'global_step': global_step,
                 'network_fn_state_dict': render_kwargs_train['network_fn'].state_dict(),
-                'network_fine_state_dict': render_kwargs_train['network_fine'].state_dict(),
                 'optimizer_state_dict': optimizer.state_dict(),
-            }, path)
+            }
+            if render_kwargs_train['network_fine'] is not None:
+                ckpt.update({'network_fine_state_dict': render_kwargs_train['network_fine'].state_dict()})
+            torch.save(ckpt, path)
             print('Saved checkpoints at', path)
 
         if i%args.i_video==0 and i > 0: