diff --git a/app/backup.py b/app/backup.py
index 49e6abe6..15c8c2e0 100644
--- a/app/backup.py
+++ b/app/backup.py
@@ -474,7 +474,8 @@ def _stop_container(self, c: Container, attempt=1) -> bool:
     def _start_container(self, c: Container, attempt=1, max_attempts: Optional[int] = None) -> bool:
         if max_attempts is None:
             start_timeout = int(self.get_label(c, "start-timeout", str(self.env.START_TIMEOUT)))
-            max_attempts = max(1, start_timeout // 2)
+            max_attempts = max(1, (start_timeout // 2) + 1)
+            self.log_this(f"Container {c.name}: start-timeout={start_timeout}s (max_attempts={max_attempts})", "DEBUG")
 
         c.reload()  # Refresh the status for this container
         status = c.status  # Read once to avoid consuming multiple mock cycles
@@ -1101,9 +1102,14 @@ def backup(self):
                     for dir in dest_dirs:
                         self._backup_additional_folders(c, dir)
 
-                if c.name not in self.containers_skipped:
+                if c.name not in self.containers_skipped and c.name not in self.containers_failed:
                     self.containers_completed.add(c.name)
                     self.log_this(f"Backup of {c.name} complete!", "INFO")
+                elif c.name in self.containers_failed and c.name not in self.containers_skipped:
+                    self.log_this(
+                        f"Backup data for {c.name} was completed, but the container failed to restart within the start timeout.",
+                        "WARN",
+                    )
 
         for dir in dest_dirs:
             self._backup_additional_folders_standalone(BeforeOrAfter.AFTER, dir)
diff --git a/pytest/test_backup.py b/pytest/test_backup.py
index 50faec30..0dbe07a6 100644
--- a/pytest/test_backup.py
+++ b/pytest/test_backup.py
@@ -2999,10 +2999,21 @@ def test_start_container_three_restarting_states_eventually_running(
                 "name": "container1",
                 "id": "123456789",
                 "labels": {"nautical-backup.start-timeout": "10"},
-                # Needs 2 retries after c.start() to reach running.
-                # With START_TIMEOUT=2 (max_attempts=1) this would fail;
-                # the label overrides to 10s (max_attempts=5) so it succeeds.
-                "status_side_effect": ["running", "exited", "exited", "exited", "restarting", "restarting", "running"],
+                # Needs 4 retries after c.start() to reach running.
+                # START_TIMEOUT=2 → max_attempts=2 (formula: (2//2)+1=2), so attempt=3 sees
+                # "restarting" and returns False — failure without the label.
+                # Label start-timeout=10 → max_attempts=6 ((10//2)+1), so it succeeds.
+                "status_side_effect": [
+                    "running",
+                    "exited",
+                    "exited",
+                    "exited",
+                    "restarting",
+                    "restarting",
+                    "restarting",
+                    "restarting",
+                    "running",
+                ],
             }
         ],
         indirect=True,
@@ -3016,7 +3027,7 @@ def test_START_TIMEOUT_label_supersedes_env(
     ):
         """Per-container start-timeout label should override the global START_TIMEOUT env var."""
         mock_subprocess_run.return_value.returncode = 0
-        monkeypatch.setenv("START_TIMEOUT", "2")  # max_attempts=1 — would fail without the label
+        monkeypatch.setenv("START_TIMEOUT", "2")  # max_attempts=2 — exhausted before container is running
 
         mock_docker_client.containers.list.return_value = [mock_container1]
         nb = NauticalBackup(mock_docker_client)
@@ -3080,6 +3091,54 @@ def test_rsync_exit_code_23_includes_symlink_hint(
         assert "symlinks" in nb.error_messages[0]
         assert "container1" in nb.containers_failed
 
+    @mock.patch("builtins.print")
+    @mock.patch("subprocess.run")
+    @pytest.mark.parametrize(
+        "mock_container1",
+        [
+            {
+                "name": "container1",
+                "id": "123456789",
+                # Container never reaches running after start — stays restarting through all attempts.
+                # START_TIMEOUT=2 → max_attempts=(2//2)+1=2.
+                # Reads: stop-check, after-stop, during-backup, attempt-1, post-start, attempt-2, attempt-3(→False)
+                "status_side_effect": [
+                    "running",
+                    "exited",
+                    "exited",
+                    "exited",
+                    "restarting",
+                    "restarting",
+                    "restarting",
+                ],
+            }
+        ],
+        indirect=True,
+    )
+    def test_start_container_exhausted_retries_not_in_completed(
+        self,
+        mock_subprocess_run: MagicMock,
+        mock_print: MagicMock,
+        mock_docker_client: MagicMock,
+        mock_container1: MagicMock,
+        monkeypatch: pytest.MonkeyPatch,
+    ):
+        """When _start_container exhausts all retries, container must be in containers_failed,
+        NOT in containers_completed, and a WARN about the partial backup should be logged."""
+        mock_subprocess_run.return_value.returncode = 0
+        monkeypatch.setenv("START_TIMEOUT", "2")  # max_attempts=2 → 3 total attempts before giving up
+
+        mock_docker_client.containers.list.return_value = [mock_container1]
+        nb = NauticalBackup(mock_docker_client)
+        nb.backup()
+
+        assert "container1" in nb.containers_failed
+        assert "container1" not in nb.containers_completed
+
+        printed = [call_args[0][0] for call_args in mock_print.call_args_list]
+        assert any("failed to restart within the start timeout" in line for line in printed)
+        assert not any("Backup of container1 complete!" in line for line in printed)
+
     # -------------------------------------------------------------------------
     # Retention policy tests
     # -------------------------------------------------------------------------