diff --git a/gio/win32/gwinhttpfile.c b/gio/win32/gwinhttpfile.c
index 160168d2f..d6c1d6f9b 100644
--- a/gio/win32/gwinhttpfile.c
+++ b/gio/win32/gwinhttpfile.c
@@ -549,7 +549,7 @@ g_winhttp_file_query_info (GFile                *file,
       gint64 cl;
       int n;
 
-      if (swscanf (content_length, L"%I64d%n", &cl, &n) == 1 &&
+      if (swscanf (content_length, L"%"G_GINT64_FORMAT"%n", &cl, &n) == 1 &&
           n == wcslen (content_length))
         g_file_info_set_size (info, cl);