diff --git a/src/devx/molecule/start_docker.py b/src/devx/molecule/start_docker.py
index c541671..289d4c1 100644
--- a/src/devx/molecule/start_docker.py
+++ b/src/devx/molecule/start_docker.py
@@ -210,6 +210,22 @@ def start_docker_daemon(timeout: int = DEFAULT_TIMEOUT) -> bool:
         if free_bytes == 0 and sock == HOST_DOCKER_SOCK:
             click.echo("Host rootless Docker root dir not accessible from container, using it")
             return True
+        # If free_bytes is 0 and there are no dockerd processes inside the
+        # container, the socket is the host's Docker (mounted from outside).
+        # The data root is on the host filesystem and has plenty of space.
+        if free_bytes == 0 and sock == DOCKER_SOCK:
+            has_inner_dockerd = False
+            with contextlib.suppress(Exception):
+                pgrep_result = subprocess.run(  # nosec B603 B607
+                    ["pgrep", "-f", "dockerd"],
+                    capture_output=True,
+                    text=True,
+                    timeout=5,
+                )
+                has_inner_dockerd = pgrep_result.returncode == 0
+            if not has_inner_dockerd:
+                click.echo("No inner dockerd found, socket is host Docker (data root on host), using it")
+                return True
         click.echo(f"  Insufficient space ({free_gb:.1f} GB), trying next...")
 
     # No socket with sufficient space found.
diff --git a/tests/unit/test_start_docker.py b/tests/unit/test_start_docker.py
index 44419a1..4da4437 100644
--- a/tests/unit/test_start_docker.py
+++ b/tests/unit/test_start_docker.py
@@ -205,8 +205,10 @@ class TestStartDockerDaemon:
         mock_ntf.return_value = MagicMock(name="/tmp/dockerd.log")
         # is_docker_ready: first check (inner dockerd) True, then local daemon checks
         mock_ready.side_effect = [True, False, False, False, False, True]
-        # subprocess.run calls: pgrep(before), pkill x3, pgrep(after), docker info, rm
+        # subprocess.run: pgrep(socket check, finds dockerd), pgrep(before kill),
+        # pkill x3, pgrep(after kill), docker info(dead), rm
         mock_run.side_effect = [
+            MagicMock(returncode=0, stdout="123 /usr/bin/dockerd\n"),  # socket check pgrep
             _pgrep_empty(),
             MagicMock(),
             MagicMock(),
@@ -218,6 +220,27 @@ class TestStartDockerDaemon:
         assert start_docker_daemon(timeout=5) is True
         mock_popen.assert_called_once()
 
+    @patch("devx.molecule.start_docker._diagnose_socket")
+    @patch("devx.molecule.start_docker._get_docker_free_bytes", return_value=0)
+    @patch("devx.molecule.start_docker.is_docker_ready", return_value=True)
+    @patch("devx.molecule.start_docker.os.path.exists", side_effect=_exists_map({DOCKER_SOCK}))
+    @patch("devx.molecule.start_docker.glob.glob", return_value=[])
+    @patch("devx.molecule.start_docker.subprocess.run")
+    def test_no_inner_dockerd_trusts_host_socket(
+        self,
+        mock_run: MagicMock,
+        mock_glob: MagicMock,
+        mock_exists: MagicMock,
+        mock_ready: MagicMock,
+        mock_free: MagicMock,
+        mock_diag: MagicMock,
+    ) -> None:
+        """Should trust /var/run/docker.sock with free=0 when no inner dockerd exists."""
+        # pgrep finds no dockerd processes (returncode=1)
+        mock_run.return_value = MagicMock(returncode=1, stdout="")
+        assert start_docker_daemon(timeout=5) is True
+        assert os.environ.get("DOCKER_HOST") == f"unix://{DOCKER_SOCK}"
+
     @patch("devx.molecule.start_docker._diagnose_socket")
     @patch("devx.molecule.start_docker._get_docker_free_bytes")
     @patch("devx.molecule.start_docker.is_docker_ready")