diff --git a/api/vm.py b/api/vm.py
index 0e9087d..2f17828 100644
--- a/api/vm.py
+++ b/api/vm.py
@@ -90,7 +90,7 @@ class DevicesInterface(BaseModel):
 
     switch_id:UUID4
     id:UUID4 = Field(default_factory=uuid4)
-    mac_addr:str = Field(default=None)
+    mac_addr:str = Field(default='')
 
 class Graphics(BaseModel):
     port:int = Field(default=-1)
@@ -121,7 +121,7 @@ class TPM(BaseModel):
 
 class Devices(BaseModel):
     disks:Optional[List[DevicesDisk]] = Field(default=None, description="Disques virtuel")
-    cdrom:DevicesCDROM = Field(default=None, description="CDROM virtuel")
+    cdrom:Optional[DevicesCDROM] = Field(default=None, description="CDROM virtuel")
     interfaces:Optional[List[DevicesInterface]] = Field(default=None, description="Interfaces réseau")
     graphics:Optional[Graphics] = Field(default=None, description="Console VNC")
     audio:Audio = Field(default=None, description="Carte Audio")