diff --git a/bob/bio/base/pipelines/vanilla_biometrics/score_writers.py b/bob/bio/base/pipelines/vanilla_biometrics/score_writers.py
index dfcf7f0b4c31fbc89205559b246c0d90c4a45e8a..9998d4a58ab180b045ad8c81b49cf4c343e527b1 100644
--- a/bob/bio/base/pipelines/vanilla_biometrics/score_writers.py
+++ b/bob/bio/base/pipelines/vanilla_biometrics/score_writers.py
@@ -34,7 +34,7 @@ class FourColumnsScoreWriter(ScoreWriter):
                 )
                 for biometric_reference in probe
             ]
-            filename = os.path.join(path, probe.subject)
+            filename = os.path.join(path, probe.subject) + ".txt"
             open(filename, "w").writelines(lines)
             checkpointed_scores.append(
                 SampleSet(