diff --git a/yaml/xyz/openbmc_project/Control/Power/ACPIPowerState.interface.yaml b/yaml/xyz/openbmc_project/Control/Power/ACPIPowerState.interface.yaml
index 2f8dd84..d7ae808 100644
--- a/yaml/xyz/openbmc_project/Control/Power/ACPIPowerState.interface.yaml
+++ b/yaml/xyz/openbmc_project/Control/Power/ACPIPowerState.interface.yaml
@@ -4,11 +4,13 @@
 properties:
     - name: SysACPIStatus
       type: enum[self.ACPI]
+      default: Unknown
       description: >
           The ACPI system power status.
 
     - name: DevACPIStatus
       type: enum[self.ACPI]
+      default: Unknown
       description: >
           The ACPI device power status.