diff --git a/src/os/win32/ngx_event_log.c b/src/os/win32/ngx_event_log.c
index e11ed1e8..dce8eddd 100644
--- a/src/os/win32/ngx_event_log.c
+++ b/src/os/win32/ngx_event_log.c
@@ -8,7 +8,9 @@
 #include <ngx_core.h>
 
 
-#define NGX_MAX_ERROR_STR   2048
+#ifndef NGX_MAX_ERROR_STR
+#define NGX_MAX_ERROR_STR   4096
+#endif
 
 
 void ngx_cdecl
