diff --git a/lib/std/os/windows.zig b/lib/std/os/windows.zig
index c2295ba80d492086e7ad934698fa4636620f5a1a..ea96e38cee094f2dbaa6257b06f4ab547a8e3ce0 100644
--- a/lib/std/os/windows.zig
+++ b/lib/std/os/windows.zig
@@ -4983,8 +4983,8 @@ pub const KAFFINITY = usize;
 pub const KPRIORITY = i32;
 
 pub const CLIENT_ID = extern struct {
-    UniqueProcess: HANDLE,
-    UniqueThread: HANDLE,
+    UniqueProcess: ?HANDLE,
+    UniqueThread: ?HANDLE,
 };
 
 pub const TEB = extern struct {