diff --git a/include/fluent-bit/flb_msgpack_append_message.h b/include/fluent-bit/flb_msgpack_append_message.h
index 25990c604f3..b2c5049febf 100644
--- a/include/fluent-bit/flb_msgpack_append_message.h
+++ b/include/fluent-bit/flb_msgpack_append_message.h
@@ -25,6 +25,7 @@
 #define FLB_MAP_NOT_MODIFIED    -1
 #define FLB_MAP_EXPANSION_ERROR -2
 #define FLB_MAP_EXPANSION_INVALID_VALUE_TYPE -3
+#define FLB_MSGPACK_UNPACK_ERROR -4
 
 #include <fluent-bit/flb_pack.h>
 #include <msgpack/unpack.h>
diff --git a/src/flb_msgpack_append_message.c b/src/flb_msgpack_append_message.c
index 8425d9a2a63..d606721702d 100644
--- a/src/flb_msgpack_append_message.c
+++ b/src/flb_msgpack_append_message.c
@@ -114,11 +114,11 @@ int flb_msgpack_append_map_to_record(char **result_buffer,
     if ((i=msgpack_unpack_next(&unpacker, map_data, map_size, &off)) !=
         MSGPACK_UNPACK_SUCCESS ) {
         msgpack_unpacked_destroy(&unpacker);
-        return FLB_MAP_EXPANSION_ERROR;
+        return FLB_MSGPACK_UNPACK_ERROR;
     }
     if (unpacker.data.type != MSGPACK_OBJECT_MAP) {
         msgpack_unpacked_destroy(&unpacker);
-        return FLB_MAP_EXPANSION_ERROR;
+        return FLB_MSGPACK_UNPACK_ERROR;
     }
 
     message_entry.val = unpacker.data;