diff --git a/main.py b/main.py
index f118ef0..06611e8 100644
--- a/main.py
+++ b/main.py
@@ -130,6 +130,19 @@ class PedalApp:
             )
             self.audio_system = AudioSystem(self.audio_config)
             self.audio_system.setup_i2s(reboot_hint=True)
+
+            # Clean stale JACK SHM segments from prior crashes before starting
+            try:
+                import shutil
+                from pathlib import Path
+                for p in Path("/dev/shm").glob("jack*"):
+                    if p.is_dir():
+                        shutil.rmtree(p, ignore_errors=True)
+                    else:
+                        p.unlink(missing_ok=True)
+            except Exception:
+                pass
+
             if self.audio_config.jack_enabled:
                 self.audio_system.start_jack(timeout=10)
             else:
diff --git a/src/system/audio.py b/src/system/audio.py
index 5ed7358..65fe328 100644
--- a/src/system/audio.py
+++ b/src/system/audio.py
@@ -359,6 +359,18 @@ class AudioSystem:
             subprocess.run(["killall", "-9", "jackd"], capture_output=True)
         except FileNotFoundError:
             pass
+        # Clean up stale JACK shared memory segments — these prevent a
+        # new JACK instance from starting if left behind after a crash
+        # or forceful kill.
+        try:
+            import shutil
+            for p in Path("/dev/shm").glob("jack*"):
+                if p.is_dir():
+                    shutil.rmtree(p, ignore_errors=True)
+                else:
+                    p.unlink(missing_ok=True)
+        except Exception:
+            pass
 
     def restart_jack(self, timeout: int = 10) -> bool:
         """Restart JACK server."""