diff --git a/gns3server/schemas/custom_adapters.py b/gns3server/schemas/custom_adapters.py
index d24b9db1..f3472540 100644
--- a/gns3server/schemas/custom_adapters.py
+++ b/gns3server/schemas/custom_adapters.py
@@ -17,6 +17,7 @@
 
 CUSTOM_ADAPTERS_ARRAY_SCHEMA = {
     "type": "array",
+    "default": [],
     "items": {
         "type": "object",
         "description": "Custom properties",
@@ -46,4 +47,3 @@ CUSTOM_ADAPTERS_ARRAY_SCHEMA = {
         "required": ["adapter_number"]
     },
 }
-
diff --git a/gns3server/schemas/docker_appliance.py b/gns3server/schemas/docker_appliance.py
index b5b6e241..8fa18b49 100644
--- a/gns3server/schemas/docker_appliance.py
+++ b/gns3server/schemas/docker_appliance.py
@@ -17,7 +17,6 @@
 
 import copy
 from .appliance import BASE_APPLIANCE_PROPERTIES
-from .custom_adapters import CUSTOM_ADAPTERS_ARRAY_SCHEMA
 
 
 DOCKER_APPLIANCE_PROPERTIES = {
@@ -76,8 +75,7 @@ DOCKER_APPLIANCE_PROPERTIES = {
         "description": "Docker extra hosts (added to /etc/hosts)",
         "type": "string",
         "default": "",
-    },
-    "custom_adapters": CUSTOM_ADAPTERS_ARRAY_SCHEMA
+    }
 }
 
 DOCKER_APPLIANCE_PROPERTIES.update(copy.deepcopy(BASE_APPLIANCE_PROPERTIES))
diff --git a/tests/handlers/api/controller/test_appliance.py b/tests/handlers/api/controller/test_appliance.py
index d856cce6..242da49f 100644
--- a/tests/handlers/api/controller/test_appliance.py
+++ b/tests/handlers/api/controller/test_appliance.py
@@ -694,7 +694,8 @@ def test_qemu_appliance_create(http_controller):
                          "qemu_path": "",
                          "ram": 512,
                          "symbol": ":/symbols/qemu_guest.svg",
-                         "usage": ""}
+                         "usage": "",
+                         "custom_adapters": []}
 
     for item, value in expected_response.items():
         assert response.json.get(item) == value
@@ -729,7 +730,8 @@ def test_vmware_appliance_create(http_controller):
                          "port_segment_size": 0,
                          "symbol": ":/symbols/vmware_guest.svg",
                          "use_any_adapter": False,
-                         "vmx_path": "/path/to/vm.vmx"}
+                         "vmx_path": "/path/to/vm.vmx",
+                         "custom_adapters": []}
 
     for item, value in expected_response.items():
         assert response.json.get(item) == value
@@ -765,7 +767,8 @@ def test_virtualbox_appliance_create(http_controller):
                          "ram": 256,
                          "symbol": ":/symbols/vbox_guest.svg",
                          "use_any_adapter": False,
-                         "vmname": "My VirtualBox VM"}
+                         "vmname": "My VirtualBox VM",
+                         "custom_adapters": []}
 
     for item, value in expected_response.items():
         assert response.json.get(item) == value