diff --git a/src/agent_gsm.py b/src/agent_gsm.py
index 0784645..8a653f1 100644
--- a/src/agent_gsm.py
+++ b/src/agent_gsm.py
@@ -38,7 +38,7 @@ BackendServer : utils_qualtest.QualtestBackend = None
 REFERENCE_AUDIO = "/dev/shm/reference.wav"
 
 # Loaded refernce audio (from backend)
-LOADED_AUDIO = "/dev/shm/loaded_audio.wav"
+LOADED_AUDIO = Path("/dev/shm/loaded_audio.wav")
 
 # Script to exec after mobile call answering
 EXEC_SCRIPT = None
@@ -278,12 +278,15 @@ def run_caller_task(t):
     task_name = t['name'].strip()
 
     # Load reference audio
+    if LOADED_AUDIO.exists():
+        os.remove(LOADED_AUDIO)
+
     if not BackendServer.load_audio(t["audio_id"], LOADED_AUDIO):
         utils.log_error('No audio is available, exiting.')
         sys.exit(EXIT_ERROR)
     
     # Use loaded audio as reference
-    REFERENCE_AUDIO = LOADED_AUDIO
+    REFERENCE_AUDIO = str(LOADED_AUDIO)
 
     CURRENT_TASK = task_name
 
diff --git a/src/utils_qualtest.py b/src/utils_qualtest.py
index b91efd0..e7dfcbf 100644
--- a/src/utils_qualtest.py
+++ b/src/utils_qualtest.py
@@ -16,7 +16,7 @@ import requests
 
 from socket import timeout
 from crontab import CronTab
-
+from pathlib import Path
 
 start_system_time = time.time()
 start_monotonic_time = time.monotonic()
@@ -171,7 +171,7 @@ class QualtestBackend:
 
     def upload_report(self, report, files) -> str:
         # UUID string as result
-        result = None 
+        result = None
         
         # Log about upload attempt
         utils.log_verbose(f"Uploading to {self.address} files {files} and report: {json.dumps(report, indent=4)}")
@@ -303,7 +303,7 @@ class QualtestBackend:
             return dict()
 
 
-    def load_audio(self, audio_id: int, output_path: str):
+    def load_audio(self, audio_id: int, output_path: Path):
         utils.log(f'Loading audio with ID: {audio_id}')
         try:
             # Build query for both V1 & V2 API