diff --git a/OpenChange/SOGoMAPIFSFolder.m b/OpenChange/SOGoMAPIFSFolder.m
index 429e23f93..b26e0ea9d 100644
--- a/OpenChange/SOGoMAPIFSFolder.m
+++ b/OpenChange/SOGoMAPIFSFolder.m
@@ -39,6 +39,7 @@
 #import "SOGoMAPIFSFolder.h"
 
 #undef DEBUG
+#include <stdbool.h>
 #include <talloc.h>
 #include <util/time.h>
 #include <mapistore/mapistore.h>