diff --git a/builtin/fsck.c b/builtin/fsck.c
index 06eb421720..b1447c2610 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -49,6 +49,7 @@ static int name_objects;
 #define ERROR_PACK 04
 #define ERROR_REFS 010
 #define ERROR_COMMIT_GRAPH 020
+#define ERROR_MULTI_PACK_INDEX 040
 
 static const char *describe_object(struct object *obj)
 {
@@ -862,7 +863,7 @@ int cmd_fsck(int argc, const char **argv, const char *prefix)
 			midx_argv[2] = "--object-dir";
 			midx_argv[3] = alt->path;
 			if (run_command(&midx_verify))
-				errors_found |= ERROR_COMMIT_GRAPH;
+				errors_found |= ERROR_MULTI_PACK_INDEX;
 		}
 	}