diff --git a/vimms/Evaluation.py b/vimms/Evaluation.py
index c5df766..249ea44 100644
--- a/vimms/Evaluation.py
+++ b/vimms/Evaluation.py
@@ -336,7 +336,7 @@ def from_aligned_boxfile(cls, reader, aligned_file, min_box_ppm=None):
                             float(inner["RT end"]) * reader.RT_FACTOR,
                             float(inner["m/z min"]),
                             float(inner["m/z max"]),
-                            round_digits=None)
+                            round_digits=None
                         ).apply_min_box_ppm(ywidth=min_box_ppm, round_digits=None)
                     )
                 else:
diff --git a/vimms/Experiment.py b/vimms/Experiment.py
index 87de8db..4420d6a 100644
--- a/vimms/Experiment.py
+++ b/vimms/Experiment.py
@@ -6,6 +6,7 @@
 import inspect
 import multiprocessing
 import json
+import uuid
 
 from vimms.Common import POSITIVE, save_obj, load_obj
 from vimms.Roi import RoiBuilderParams
@@ -304,7 +305,7 @@ def _gen_chems(fs, ionisation_mode, out_dir, point_noise_threshold, chem_noise_t
         generated = cm.sample(None, 2, source_polarity=ionisation_mode)
         
         basename = ".".join(os.path.basename(fs).split(".")[:-1])
-        ppath = os.path.join(out_dir, f"{basename}_temp.pkl")
+        ppath = os.path.join(out_dir, f"{basename}_temp_{uuid.uuid4()}.pkl")
         ChemSet.dump_chems(generated, ppath)
         
         return ppath