diff --git a/docker/entrypoint.sh b/docker/entrypoint.sh
index d85df72..a96488a 100755
--- a/docker/entrypoint.sh
+++ b/docker/entrypoint.sh
@@ -8,6 +8,7 @@ DISPLAY_NUM="${VNC_DISPLAY_NUM:-99}"
 VNC_PORT="${VNC_PORT:-5900}"
 NOVNC_PORT="${NOVNC_PORT:-6080}"
 GEOMETRY="${SCREEN_GEOMETRY:-1280x800x24}"
+BROWSER_SESSION_DIR="${BROWSER_SESSION_DIR:-/app/data/browser-session}"
 export DISPLAY=":${DISPLAY_NUM}"
 
 # noVNC ships under different paths depending on the distro; find the web root once.
@@ -29,6 +30,15 @@ fi
 # to bind to the display and the bot starts up with no X server.
 rm -f "/tmp/.X${DISPLAY_NUM}-lock" "/tmp/.X11-unix/X${DISPLAY_NUM}" 2>/dev/null || true
 
+# Persistent profiles retain Chromium's singleton artifacts when a container
+# is replaced before Chromium exits cleanly. Remove only those locks; cookies,
+# local storage, and the rest of the authenticated profile remain untouched.
+rm -f \
+  "${BROWSER_SESSION_DIR}/SingletonLock" \
+  "${BROWSER_SESSION_DIR}/SingletonSocket" \
+  "${BROWSER_SESSION_DIR}/SingletonCookie" \
+  2>/dev/null || true
+
 echo "[entrypoint] starting Xvfb on ${DISPLAY} (${GEOMETRY})"
 Xvfb "${DISPLAY}" -screen 0 "${GEOMETRY}" -ac +extension RANDR &
 XVFB_PID=$!
diff --git a/tests/vnc-entrypoint.test.ts b/tests/vnc-entrypoint.test.ts
index 4cf752f..23623d9 100644
--- a/tests/vnc-entrypoint.test.ts
+++ b/tests/vnc-entrypoint.test.ts
@@ -13,4 +13,13 @@ describe('VNC container entrypoint', () => {
       script.indexOf('starting noVNC'),
     );
   });
+
+  it('removes only stale Chromium singleton artifacts before launching the bot', () => {
+    const script = fs.readFileSync(path.resolve('docker/entrypoint.sh'), 'utf8');
+
+    expect(script).toContain('"${BROWSER_SESSION_DIR}/SingletonLock"');
+    expect(script).toContain('"${BROWSER_SESSION_DIR}/SingletonSocket"');
+    expect(script).toContain('"${BROWSER_SESSION_DIR}/SingletonCookie"');
+    expect(script.indexOf('SingletonLock')).toBeLessThan(script.indexOf('launching bot'));
+  });
 });