diff --git a/programs/copier/ZooKeeperStaff.h b/programs/copier/ZooKeeperStaff.h
index f5224857259..edd0d9e43d2 100644
--- a/programs/copier/ZooKeeperStaff.h
+++ b/programs/copier/ZooKeeperStaff.h
@@ -187,7 +187,7 @@ public:
                                 stale->store(true);
                                 break;
                             case Coordination::CHANGED:
-                                LOG_DEBUG(logger, "CleanStateClock change: CHANGED, at{}", rsp.path);
+                                LOG_DEBUG(logger, "CleanStateClock change: CHANGED, at {}", rsp.path);
                                 stale->store(true);
                         }
                     }