diff --git a/gns3server/modules/dynamips/nodes/router.py b/gns3server/modules/dynamips/nodes/router.py
index f79f0b0b..b3196ac9 100644
--- a/gns3server/modules/dynamips/nodes/router.py
+++ b/gns3server/modules/dynamips/nodes/router.py
@@ -1521,7 +1521,6 @@ class Router(BaseVM):
             if startup_config_base64:
                 if not self.startup_config:
                     self._startup_config = os.path.join("configs", "i{}_startup-config.cfg".format(self._dynamips_id))
-
                 try:
                     config = base64.b64decode(startup_config_base64).decode("utf-8", errors="replace")
                     config = "!\n" + config.replace("\r", "")
@@ -1532,13 +1531,11 @@ class Router(BaseVM):
                 except (binascii.Error, OSError) as e:
                     raise DynamipsError("Could not save the startup configuration {}: {}".format(config_path, e))
 
-            if private_config_base64:
+            if private_config_base64 and base64.b64decode(private_config_base64) != b'\nkerberos password \nend\n':
                 if not self.private_config:
                     self._private_config = os.path.join("configs", "i{}_private-config.cfg".format(self._dynamips_id))
-
                 try:
                     config = base64.b64decode(private_config_base64).decode("utf-8", errors="replace")
-                    config = "!\n" + config.replace("\r", "")
                     config_path = os.path.join(module_workdir, self.private_config)
                     with open(config_path, "wb") as f:
                         log.info("saving private-config to {}".format(self.private_config))
diff --git a/gns3server/modules/iou/iou_vm.py b/gns3server/modules/iou/iou_vm.py
index 303c078e..fb610ccf 100644
--- a/gns3server/modules/iou/iou_vm.py
+++ b/gns3server/modules/iou/iou_vm.py
@@ -108,7 +108,6 @@ class IOUVM(BaseVM):
                         self.manager.port_manager.release_udp_port(nio.lport, self._project)
 
         yield from self.stop()
-        self.save_configs()
 
     @property
     def path(self):
@@ -681,6 +680,7 @@ class IOUVM(BaseVM):
             self._iouyap_process = None
 
         self._started = False
+        self.save_configs()
 
     def _terminate_process_iouyap(self):
         """
@@ -1097,7 +1097,7 @@ class IOUVM(BaseVM):
             if private_config is None:
                 private_config = ''
 
-            # We disallow erasing the startup config file
+            # We disallow erasing the private config file
             if len(private_config) == 0 and os.path.exists(private_config_path):
                 return
 
@@ -1204,18 +1204,16 @@ class IOUVM(BaseVM):
                 config_path = os.path.join(self.working_dir, "startup-config.cfg")
                 try:
                     config = startup_config_content.decode("utf-8", errors="replace")
-                    config = "!\n" + config.replace("\r", "")
                     with open(config_path, "wb") as f:
                         log.info("saving startup-config to {}".format(config_path))
                         f.write(config.encode("utf-8"))
                 except (binascii.Error, OSError) as e:
                     raise IOUError("Could not save the startup configuration {}: {}".format(config_path, e))
 
-            if private_config_content:
+            if private_config_content and private_config_content != b'\nend\n':
                 config_path = os.path.join(self.working_dir, "private-config.cfg")
                 try:
                     config = private_config_content.decode("utf-8", errors="replace")
-                    config = "!\n" + config.replace("\r", "")
                     with open(config_path, "wb") as f:
                         log.info("saving private-config to {}".format(config_path))
                         f.write(config.encode("utf-8"))