diff --git a/gns3server/modules/iou/iou_vm.py b/gns3server/modules/iou/iou_vm.py
index ee8cc1ed..1bfa2e6d 100644
--- a/gns3server/modules/iou/iou_vm.py
+++ b/gns3server/modules/iou/iou_vm.py
@@ -952,8 +952,13 @@ class IOUVM(BaseVM):
 
         try:
             script_file = os.path.join(self.working_dir, "initial-config.cfg")
+
+            # We disallow erasing the initial config file
+            if len(initial_config) == 0 and os.path.exists(script_file):
+                return
+
             with open(script_file, 'w+') as f:
-                if initial_config is None:
+                if len(initial_config) == 0:
                     f.write('')
                 else:
                     initial_config = initial_config.replace("%h", self._name)
diff --git a/tests/modules/iou/test_iou_vm.py b/tests/modules/iou/test_iou_vm.py
index 9159f00b..7885fd6c 100644
--- a/tests/modules/iou/test_iou_vm.py
+++ b/tests/modules/iou/test_iou_vm.py
@@ -265,6 +265,18 @@ def test_update_initial_config(vm):
         assert f.read() == content
 
 
+def test_update_initial_config_empty(vm):
+    content = "service timestamps debug datetime msec\nservice timestamps log datetime msec\nno service password-encryption"
+    vm.initial_config = content
+    filepath = os.path.join(vm.working_dir, "initial-config.cfg")
+    assert os.path.exists(filepath)
+    with open(filepath) as f:
+        assert f.read() == content
+    vm.initial_config = ""
+    with open(filepath) as f:
+        assert f.read() == content
+
+
 def test_update_initial_config_h(vm):
     content = "hostname %h\n"
     vm.name = "pc1"