diff --git a/pupil_src/shared_modules/file_methods.py b/pupil_src/shared_modules/file_methods.py
index 3afcf892c8..e11a4bca45 100644
--- a/pupil_src/shared_modules/file_methods.py
+++ b/pupil_src/shared_modules/file_methods.py
@@ -42,7 +42,9 @@ def __init__(self, file_path, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.file_path = os.path.expanduser(file_path)
         try:
-            self.update(**load_object(self.file_path, allow_legacy=False))
+            if os.path.getsize(file_path) > 0:
+                # Only try to load object if file is not empty
+                self.update(**load_object(self.file_path, allow_legacy=False))
         except IOError:
             logger.debug(
                 f"Session settings file '{self.file_path}' not found."
diff --git a/pupil_src/shared_modules/surface_tracker/background_tasks.py b/pupil_src/shared_modules/surface_tracker/background_tasks.py
index 6464a3ab32..e1bd860432 100644
--- a/pupil_src/shared_modules/surface_tracker/background_tasks.py
+++ b/pupil_src/shared_modules/surface_tracker/background_tasks.py
@@ -19,6 +19,10 @@
 
 import background_helper
 import player_methods
+import file_methods
+
+from .surface_marker import Surface_Marker
+
 
 logger = logging.getLogger(__name__)
 
@@ -221,6 +225,7 @@ def get_export_proxy(
     gaze_positions,
     fixations,
     camera_model,
+    marker_cache_path,
     mp_context,
 ):
     exporter = Exporter(
@@ -231,6 +236,7 @@ def get_export_proxy(
         gaze_positions,
         fixations,
         camera_model,
+        marker_cache_path,
     )
     proxy = background_helper.IPC_Logging_Task_Proxy(
         "Offline Surface Tracker Exporter",
@@ -250,6 +256,7 @@ def __init__(
         gaze_positions,
         fixations,
         camera_model,
+        marker_cache_path,
     ):
         self.export_range = export_range
         self.metrics_dir = os.path.join(export_dir, "surfaces")
@@ -260,6 +267,7 @@ def __init__(
         self.camera_model = camera_model
         self.gaze_on_surfaces = None
         self.fixations_on_surfaces = None
+        self.marker_cache_path = marker_cache_path
 
     def save_surface_statisics_to_file(self):
         logger.info("exporting metrics to {}".format(self.metrics_dir))
@@ -298,6 +306,17 @@ def save_surface_statisics_to_file(self):
                 "Saved surface gaze and fixation data for '{}'".format(surface.name)
             )
 
+        # Cleanup surface related data to release memory
+        self.surfaces = None
+        self.fixations = None
+        self.gaze_positions = None
+        self.gaze_on_surfaces = None
+        self.fixations_on_surfaces = None
+
+        # Perform marker export *after* surface data is released
+        # to avoid holding everything in memory all at once.
+        self._export_marker_detections()
+
         logger.info("Done exporting reference surface data.")
         return
 
@@ -338,6 +357,46 @@ def _map_gaze_and_fixations(self):
 
         return gaze_on_surface, fixations_on_surface
 
+    def _export_marker_detections(self):
+
+        # Load the temporary marker cache created by the offline surface tracker
+        marker_cache = file_methods.Persistent_Dict(self.marker_cache_path)
+        marker_cache = marker_cache["marker_cache"]
+
+        try:
+            file_path = os.path.join(self.metrics_dir, "marker_detections.csv")
+            with open(file_path, "w", encoding="utf-8", newline="") as csv_file:
+                csv_writer = csv.writer(csv_file, delimiter=",")
+                csv_writer.writerow(
+                    (
+                        "world_index",
+                        "marker_uid",
+                        "corner_0_x",
+                        "corner_0_y",
+                        "corner_1_x",
+                        "corner_1_y",
+                        "corner_2_x",
+                        "corner_2_y",
+                        "corner_3_x",
+                        "corner_3_y",
+                    )
+                )
+                for idx, serialized_markers in enumerate(marker_cache):
+                    for m in map(Surface_Marker.deserialize, serialized_markers):
+                        flat_corners = [x for c in m.verts_px for x in c[0]]
+                        assert len(flat_corners) == 8  # sanity check
+                        csv_writer.writerow(
+                            (
+                                idx,
+                                m.uid,
+                                *flat_corners,
+                            )
+                        )
+        finally:
+            # Delete the temporary marker cache created by the offline surface tracker
+            os.remove(self.marker_cache_path)
+            self.marker_cache_path = None
+
     def _export_surface_visibility(self):
         with open(
             os.path.join(self.metrics_dir, "surface_visibility.csv"),
diff --git a/pupil_src/shared_modules/surface_tracker/surface_tracker_offline.py b/pupil_src/shared_modules/surface_tracker/surface_tracker_offline.py
index 86cdbc4550..9094085155 100644
--- a/pupil_src/shared_modules/surface_tracker/surface_tracker_offline.py
+++ b/pupil_src/shared_modules/surface_tracker/surface_tracker_offline.py
@@ -14,6 +14,7 @@
 import multiprocessing
 import os
 import platform
+import tempfile
 import time
 import typing as T
 
@@ -559,6 +560,16 @@ def on_notify(self, notification):
                     break
 
         elif notification["subject"] == "should_export":
+            # Create new marker cache temporary file
+            # Backgroud exporter is responsible of removing the temporary file when finished
+            file_handle, marker_cache_path = tempfile.mkstemp()
+            os.close(file_handle)  # https://bugs.python.org/issue42830
+
+            # Save marker cache into the new temporary file
+            temp_marker_cache = file_methods.Persistent_Dict(marker_cache_path)
+            temp_marker_cache["marker_cache"] = self.marker_cache
+            temp_marker_cache.save()
+
             proxy = background_tasks.get_export_proxy(
                 notification["export_dir"],
                 notification["range"],
@@ -567,6 +578,7 @@ def on_notify(self, notification):
                 self.g_pool.gaze_positions,
                 self.g_pool.fixations,
                 self.camera_model,
+                marker_cache_path,
                 mp_context,
             )
             self.export_proxies.add(proxy)