diff --git a/src/dynalab_core/__init__.py b/src/dynalab_core/__init__.py
index 0b4c8c8..b6d389f 100644
--- a/src/dynalab_core/__init__.py
+++ b/src/dynalab_core/__init__.py
@@ -48,6 +48,7 @@ class Core:
         self._recording = threading.Event()
         self._recording_buffer = ValueBuffer()
         self._recording_timestamp: datetime = datetime.now(timezone.utc)
+        self._offload_buffer: DLPak | None = None
         self._processing_buffer: DLPak | None = None
         self._core_version: VersionDescriptor = CORE_VERSION
         self._stop_event: threading.Event = threading.Event()
@@ -248,7 +249,7 @@ class Core:
         if input is None:
             if self._processing_buffer is None:
                 raise CoreError(
-                    "Cannot load playback because no recording is available",
+                    "Cannot load playback because no processing buffer is available",
                     code="no_playback_data",
                 )
             loaded_data = copy(self._processing_buffer)
@@ -257,7 +258,33 @@ class Core:
         self._playback_engine.set_data(loaded_data)
 
     def load_processing_buffer(self, input: Path | None = None) -> None:
-        pass
+        if self._mode.value != "offline":
+            raise CoreError(
+                "Cannot load processing unless the core is in 'offline' mode",
+                code="invalid_mode",
+            )
+
+        if input is None:
+            if self._offload_buffer is None:
+                raise CoreError(
+                    "Cannot load processing because no recording buffer is available",
+                    code="no_playback_data",
+                )
+            loaded_data = DLPak().set_data(copy(self._recording_buffer))
+            connector_signal_descriptors = (
+                self._connector_registry.get_all_signal_descriptors()
+            )
+            derive_signal_descriptors = (
+                self._derive_registry.get_all_signal_descriptors()
+            )
+
+            loaded_data.set_manifest(
+                self._recording_timestamp,
+                connector_signal_descriptors + derive_signal_descriptors,
+            )
+        else:
+            loaded_data = DLPak().read(input)
+        self._processing_buffer = loaded_data
 
     # def unload_playback_engine
 
@@ -298,13 +325,14 @@ class Core:
         time.sleep(1)
         self._recording_buffer.normalize()
         self._recording_buffer.sort()
-        self._processing_buffer = DLPak().set_data(copy(self._recording_buffer))
+        self._offload_buffer = DLPak()
+        self._offload_buffer.set_data(copy(self._recording_buffer))
         connector_signal_descriptors = (
             self._connector_registry.get_all_signal_descriptors()
         )
         derive_signal_descriptors = self._derive_registry.get_all_signal_descriptors()
 
-        self._processing_buffer.set_manifest(
+        self._offload_buffer.set_manifest(
             self._recording_timestamp,
             connector_signal_descriptors + derive_signal_descriptors,
         )
diff --git a/src/dynalab_core/derive.py b/src/dynalab_core/derive.py
index 829d5f0..769b03d 100644
--- a/src/dynalab_core/derive.py
+++ b/src/dynalab_core/derive.py
@@ -255,11 +255,16 @@ class DeriveRegistry:
                 code="invalid_source",
             )
 
+        pure_input_signals = [
+            signal.to_pure() for signal in dlunit._manifest.input_signals
+        ]
+        pure_return_signal = dlunit._manifest.return_signal.to_pure()
+
         unit = DeriveUnit(
             unit_id,
             functions[0],
-            dlunit._manifest.input_signals,
-            dlunit._manifest.return_signal,
+            pure_input_signals,
+            pure_return_signal,
             self._core_input_queue,
         )