diff --git a/forgetest/forgetest/runner.py b/forgetest/forgetest/runner.py
index 7710731..c3f1248 100644
--- a/forgetest/forgetest/runner.py
+++ b/forgetest/forgetest/runner.py
@@ -544,6 +544,7 @@ class Runner:
         self.batch = None
         self.fixture = None       # the bench actuator, when one is up (fixture.py)
         self._fixture_probed = 0.0
+        self._fixture_lock = threading.Lock()
         self._fixture_said = None
         self.boot_ref = None
         self.recover()
@@ -568,25 +569,29 @@ class Runner:
         """The fixture, up and answering, or None; re-probed at most every
         FIXTURE_PROBE_S unless forced (before a run). A probe that finds
         it gone, or a config that appeared, changes the queues' routing
-        from then on."""
-        now = time.time()
-        if not force and now - self._fixture_probed < FIXTURE_PROBE_S:
-            return self.fixture
-        self._fixture_probed = now
-        had = self.fixture
-        # a box that is not there is said once, not every probe
-        said = []
-        fx = _fixture.probe(said.append)
-        for m in said:
-            if m != self._fixture_said:
-                self._note(m)
-                self._fixture_said = m
-        if fx is not None:
-            self._fixture_said = None
-        if fx is None and had is not None:
-            self._note("fixture: %s no longer answers - running without it" % had.hostname)
-        self.fixture = fx
-        return fx
+        from then on. One probe at a time, and the probe counts from its
+        completion: a caller that arrives while another's probe is in
+        flight (a page poll and a queue start right after the daemon
+        came up) waits for its answer instead of reading the stale
+        fixture, which routed the fixture's tests to nobody."""
+        with self._fixture_lock:
+            if not force and time.time() - self._fixture_probed < FIXTURE_PROBE_S:
+                return self.fixture
+            had = self.fixture
+            # a box that is not there is said once, not every probe
+            said = []
+            fx = _fixture.probe(said.append)
+            for m in said:
+                if m != self._fixture_said:
+                    self._note(m)
+                    self._fixture_said = m
+            if fx is not None:
+                self._fixture_said = None
+            if fx is None and had is not None:
+                self._note("fixture: %s no longer answers - running without it" % had.hostname)
+            self.fixture = fx
+            self._fixture_probed = time.time()
+            return fx
 
     def fixture_channels(self):
         """The channels the fixture covers right now (the button only
diff --git a/forgetest/forgetest/suite/update.py b/forgetest/forgetest/suite/update.py
index 312fed3..bf1b6e1 100644
--- a/forgetest/forgetest/suite/update.py
+++ b/forgetest/forgetest/suite/update.py
@@ -96,7 +96,8 @@ def slots_and_signature(ctx):
             ctx.log("slot %s is selected for the next boot: the apply is refused before the "
                     "signature check, which is its own guard", target)
         else:
-            ctx.check(st == 200, "the apply job did not start: %s %s", st, body)
+            ctx.check(st == 202 and isinstance(body, dict) and body.get("started") is True,
+                      "the apply job did not start: %s %s", st, body)
             result = None
             t0 = time.time()
             while time.time() - t0 < 60:
diff --git a/forgetest/tests/test_fixture.py b/forgetest/tests/test_fixture.py
index 6ae84ee..e7bcffb 100644
--- a/forgetest/tests/test_fixture.py
+++ b/forgetest/tests/test_fixture.py
@@ -416,6 +416,26 @@ class RoutingTests(unittest.TestCase):
         self.assertEqual(av["unattended"], ["r.auto"])
         self.assertIsNone(summary)
 
+    def test_a_queue_started_during_a_probe_waits_for_the_fixture(self):
+        # The daemon just came up: nothing probed yet, a page poll starts
+        # the first probe (slow: an mDNS answer), and the queue start
+        # lands while it is in flight. The start must see the fixture.
+        stub = self.stub
+
+        def slow_probe(log, path=None, resolver=None):
+            time.sleep(0.5)
+            return stub
+        fx.probe = slow_probe
+        self.runner._fixture_probed = 0.0
+        self.runner.fixture = None
+        poll = threading.Thread(target=self.runner.probe_fixture)
+        poll.start()
+        time.sleep(0.1)
+        order = self.runner.batch_selection("unattended")
+        poll.join()
+        self.assertIn("r.lid", order)
+        self.assertIn("r.btn", order)
+
     def run_queue(self, group, ack_live=False):
         ok, msg, order = self.runner.start_batch(group, ack_live=ack_live)
         self.assertTrue(ok, msg)