diff --git a/frame/tracking/pulse.py b/frame/tracking/pulse.py
index 47d87aa..deda229 100644
--- a/frame/tracking/pulse.py
+++ b/frame/tracking/pulse.py
@@ -89,7 +89,7 @@ class Capture:
         self.submitted = set()
         self.futures = {}
         self.new = set()  # every capture directory that appeared during our run
-        self.before = set()
+        self.before = None  # capture directories that existed before the run
         self.log = None
 
     def candidates(self):
@@ -192,7 +192,8 @@ class Capture:
 
     def discard(self):
         """Delete the eye images written so far, without reading them."""
-        self.new |= self.candidates() - self.before
+        if self.before is not None:
+            self.new |= self.candidates() - self.before
         for directory in self.new | ({self.directory} if self.directory else set()):
             if str(directory).startswith(self.PREFIX) and directory.is_dir() and not directory.is_symlink():
                 for entry in os.scandir(directory):
@@ -259,6 +260,11 @@ class Capture:
         """Remove every capture directory that appeared during the run. Eye
         images must not outlive it, so a failure to delete is an error."""
         left = []
+        if self.before is not None:
+            try:
+                self.new |= self.candidates() - self.before  # even if interrupted before the first poll
+            except OSError:
+                pass
         for directory in self.new | ({self.directory} if self.directory else set()):
             if str(directory).startswith(self.PREFIX) and directory.is_dir() and not directory.is_symlink():
                 try:
diff --git a/scripts/heart-check.py b/scripts/heart-check.py
index 048c429..9b3b05d 100644
--- a/scripts/heart-check.py
+++ b/scripts/heart-check.py
@@ -139,7 +139,7 @@ def read_health(path, start, end):
                 try:
                     when = parse_time(element.get("startDate") or "")
                     value = round(float(element.get("value") or ""))
-                except ValueError:
+                except (ValueError, OverflowError):
                     continue
                 if start <= when <= end:
                     samples.append((when, value))
diff --git a/tests/test_pulse.py b/tests/test_pulse.py
index 31f55fd..fdd3208 100644
--- a/tests/test_pulse.py
+++ b/tests/test_pulse.py
@@ -339,6 +339,23 @@ class CaptureLifecycle(unittest.TestCase):
         self.assertIn("etcalib_a", str(raised.exception))
         self.assertFalse(second.exists())
 
+    def test_removes_a_directory_seen_only_at_the_end(self):
+        capture = pulse.Capture(20)
+        capture.PREFIX = str(self.root / "etcalib_")
+        capture.before = capture.candidates()
+        late = self.root / "etcalib_late"
+        late.mkdir()
+        (late / "left_0.png").write_bytes(b"png")
+        capture.remove()
+        self.assertFalse(late.exists())
+        self.assertTrue((self.root / "etcalib_older").exists())
+
+    def test_never_adopts_directories_without_a_baseline(self):
+        capture = pulse.Capture(20)
+        capture.PREFIX = str(self.root / "etcalib_")
+        capture.remove()
+        self.assertTrue((self.root / "etcalib_older").exists())
+
     def test_only_removes_capture_directories(self):
         capture = pulse.Capture(20)
         capture.directory = self.root
@@ -437,6 +454,12 @@ class HeartCheck(unittest.TestCase):
                                          str(self.write("bad.xml", "<not closed"))]), 1)
         self.assertEqual(shown.getvalue().count("Could not compare"), 2)
 
+    def test_health_records_with_non_finite_values_are_skipped(self):
+        record = '<Record type="HKQuantityTypeIdentifierHeartRate" startDate="2026-09-29 12:00:00 +1000" value="%s"/>'
+        path = self.write("export.xml", "<HealthData>" + record % "inf" + record % "72" + "</HealthData>")
+        start = check.parse_time("2026-09-29 12:00:00 +1000")
+        self.assertEqual(check.read_health(path, start - 1, start + 1), [(start, 72)])
+
     def test_time_formats(self):
         self.assertEqual(check.parse_time("1700000000.5"), 1700000000.5)
         self.assertEqual(check.parse_time("2023-11-14T22:13:20Z"), 1700000000)