diff --git a/base/services/umpnpmgr/umpnpmgr.c b/base/services/umpnpmgr/umpnpmgr.c
index 656a89d0bbe..4248879a50f 100644
--- a/base/services/umpnpmgr/umpnpmgr.c
+++ b/base/services/umpnpmgr/umpnpmgr.c
@@ -3433,7 +3433,6 @@ PNP_QueryArbitratorFreeData(
     RESOURCEID ResourceID,
     DWORD ulFlags)
 {
-    UNIMPLEMENTED;
     return CR_CALL_NOT_IMPLEMENTED;
 }
 
@@ -3448,7 +3447,9 @@ PNP_QueryArbitratorFreeSize(
     RESOURCEID ResourceID,
     DWORD ulFlags)
 {
-    UNIMPLEMENTED;
+    if (pulSize != NULL)
+        *pulSize = 0;
+
     return CR_CALL_NOT_IMPLEMENTED;
 }