diff --git a/reactos/ntoskrnl/io/pnpmgr/pnproot.c b/reactos/ntoskrnl/io/pnpmgr/pnproot.c
index beaa4051959..150ea9a778e 100644
--- a/reactos/ntoskrnl/io/pnpmgr/pnproot.c
+++ b/reactos/ntoskrnl/io/pnpmgr/pnproot.c
@@ -169,7 +169,7 @@ PnpRootCreateDevice(
     Status = STATUS_NO_MEMORY;
     goto cleanup;
   }
-  RtlZeroMemory(Device, sizeof(Device));
+  RtlZeroMemory(Device, sizeof(PNPROOT_DEVICE));
   if (!RtlCreateUnicodeString(&Device->DeviceID, DevicePath))
   {
     Status = STATUS_NO_MEMORY;