diff --git a/windows/mpconfigport.h b/windows/mpconfigport.h
index ccf8768bf..da49bc0dc 100644
--- a/windows/mpconfigport.h
+++ b/windows/mpconfigport.h
@@ -82,6 +82,7 @@
 #define MICROPY_STACKLESS           (0)
 #define MICROPY_STACKLESS_STRICT    (0)
 
+#define MICROPY_PY_UERRNO           (1)
 #define MICROPY_PY_UCTYPES          (1)
 #define MICROPY_PY_UZLIB            (1)
 #define MICROPY_PY_UJSON            (1)