diff --git a/src/batdetect2/train/callbacks.py b/src/batdetect2/train/callbacks.py
index 2557e07..d973c37 100644
--- a/src/batdetect2/train/callbacks.py
+++ b/src/batdetect2/train/callbacks.py
@@ -1,6 +1,3 @@
-import os
-from functools import partial
-from multiprocessing import Pool
 from typing import List, Optional, Tuple
 
 from lightning import LightningModule, Trainer
@@ -170,19 +167,14 @@ def _match_all_collected_examples(
     targets: TargetProtocol,
     config: Optional[MatchConfig] = None,
 ) -> List[MatchEvaluation]:
-    logger.info("Matching all annotations and predictions")
-
-    with Pool() as p:
-        matches = p.starmap(
-            partial(
-                match_sound_events_and_raw_predictions,
-                targets=targets,
-                config=config,
-            ),
-            pre_matches,
+    logger.info("Matching all annotations and predictions...")
+    return [
+        match
+        for clip_annotation, raw_predictions in pre_matches
+        for match in match_sound_events_and_raw_predictions(
+            clip_annotation, raw_predictions, targets=targets, config=config
         )
-
-    return [match for clip_matches in matches for match in clip_matches]
+    ]
 
 
 def _is_in_subclip(