1 files changed, 2 insertions, 1 deletions
diff --git a/src/src/string.c b/src/src/string.c
index 365eaec03..f216e5a86 100644
--- a/src/src/string.c
+++ b/src/src/string.c
@@ -717,7 +717,8 @@ uschar buffer[STRING_SPRINTF_BUFFER_SIZE];
 va_start(ap, format);
 if (!string_vformat(buffer, sizeof(buffer), format, ap))
   log_write(0, LOG_MAIN|LOG_PANIC_DIE,
-    "string_sprintf expansion was longer than " SIZE_T_FMT, sizeof(buffer));
+    "string_sprintf expansion was longer than " SIZE_T_FMT " (%s)",
+    sizeof(buffer), format);
 va_end(ap);
 return string_copy(buffer);
 }