diff --git a/scriptworker/cot/verify.py b/scriptworker/cot/verify.py
index def93c00..43587daa 100644
--- a/scriptworker/cot/verify.py
+++ b/scriptworker/cot/verify.py
@@ -2192,7 +2192,7 @@ async def verify_chain_of_trust(chain):
         CoTError: on failure
 
     """
-    log_path = os.path.join(chain.context.config["task_log_dir"], "chain_of_trust.log")
+    log_path = os.path.join(chain.context.config["task_log_dir"], "live_backing.log")
     scriptworker_log = logging.getLogger('scriptworker')
     with contextual_log_handler(
         chain.context, path=log_path, log_obj=scriptworker_log,
diff --git a/scriptworker/log.py b/scriptworker/log.py
index 07244a8d..4b456386 100644
--- a/scriptworker/log.py
+++ b/scriptworker/log.py
@@ -112,7 +112,7 @@ def get_log_filehandle(context):
     """
     log_file_name = get_log_filename(context)
     makedirs(context.config['task_log_dir'])
-    with open(log_file_name, "w", encoding="utf-8") as filehandle:
+    with open(log_file_name, "a", encoding="utf-8") as filehandle:
         yield filehandle
 
 
diff --git a/scriptworker/test/test_integration.py b/scriptworker/test/test_integration.py
index e8a28de7..8e4f7ae5 100644
--- a/scriptworker/test/test_integration.py
+++ b/scriptworker/test/test_integration.py
@@ -272,11 +272,8 @@ async def test_shutdown():
     async with get_context(partial_config) as context:
         result = await create_task(context, task_id, task_id)
         assert result['status']['state'] == 'pending'
-        fake_cot_log = os.path.join(context.config['artifact_dir'], 'public', 'logs', 'chain_of_trust.log')
         fake_other_artifact = os.path.join(context.config['artifact_dir'], 'public', 'artifact.apk')
 
-        with open(fake_cot_log, 'w') as file:
-            file.write('CoT logs')
         with open(fake_other_artifact, 'w') as file:
             file.write('unrelated artifact')
         cancel_fut = asyncio.ensure_future(do_shutdown(context))
@@ -289,17 +286,12 @@ async def test_shutdown():
         log_url = context.queue.buildUrl(
             'getArtifact', task_id, 0, 'public/logs/live_backing.log'
         )
-        cot_log_url = context.queue.buildUrl(
-            'getArtifact', task_id, 0, 'public/logs/chain_of_trust.log'
-        )
         other_artifact_url = context.queue.buildUrl(
             'getArtifact', task_id, 0, 'public/artifact.apk'
         )
         log_path = os.path.join(context.config['work_dir'], 'log')
-        cot_log_path = os.path.join(context.config['work_dir'], 'cot_log')
         other_artifact_path = os.path.join(context.config['work_dir'], 'artifact.apk')
         await utils.download_file(context, log_url, log_path)
-        await utils.download_file(context, cot_log_url, cot_log_path)
         with pytest.raises(Download404):
             await utils.download_file(context, other_artifact_url, other_artifact_path)
 
@@ -307,10 +299,6 @@ async def test_shutdown():
             contents = fh.read()
         assert contents.rstrip() == "running task script\nAutomation Error: python exited with signal -15"
 
-        with open(cot_log_path) as fh:
-            contents = fh.read()
-        assert contents.rstrip() == "CoT logs"
-
 
 # empty_queue {{{1
 @pytest.mark.skipif(os.environ.get("NO_TESTS_OVER_WIRE"), reason=SKIP_REASON)
diff --git a/scriptworker/test/test_worker.py b/scriptworker/test/test_worker.py
index 437b13f5..21cd7323 100644
--- a/scriptworker/test/test_worker.py
+++ b/scriptworker/test/test_worker.py
@@ -405,7 +405,7 @@ async def test_run_tasks_cancel_cot(context, mocker):
 
     mock_prepare_task.assert_called_once()
     mock_complete_task.assert_called_once_with(mock.ANY, STATUSES['worker-shutdown'])
-    mock_do_upload.assert_called_once_with(context, ['public/logs/chain_of_trust.log', 'public/logs/live_backing.log'])
+    mock_do_upload.assert_called_once_with(context, ['public/logs/live_backing.log'])
 
 
 @pytest.mark.asyncio
@@ -445,7 +445,7 @@ async def mock_run_task(_, to_cancellable_process):
     assert task_process.stopped_due_to_worker_shutdown
     mock_prepare_task.assert_called_once()
     mock_complete_task.assert_called_once_with(mock.ANY, STATUSES['worker-shutdown'])
-    mock_do_upload.assert_called_once_with(context, ['public/logs/chain_of_trust.log', 'public/logs/live_backing.log'])
+    mock_do_upload.assert_called_once_with(context, ['public/logs/live_backing.log'])
 
 
 @pytest.mark.asyncio
@@ -527,7 +527,7 @@ async def mock_do_run_task(_, __, to_cancellable_process):
 
     mock_prepare_task.assert_called_once()
     mock_complete_task.assert_called_once_with(mock.ANY, STATUSES['worker-shutdown'])
-    mock_do_upload.assert_called_once_with(context, ['public/logs/chain_of_trust.log', 'public/logs/live_backing.log'])
+    mock_do_upload.assert_called_once_with(context, ['public/logs/live_backing.log'])
 
 
 @pytest.mark.asyncio
diff --git a/scriptworker/worker.py b/scriptworker/worker.py
index 296b22a8..cfc4e586 100644
--- a/scriptworker/worker.py
+++ b/scriptworker/worker.py
@@ -137,7 +137,7 @@ async def invoke(self, context):
                     artifacts_paths = filepaths_in_dir(context.config['artifact_dir'])
                 except WorkerShutdownDuringTask:
                     shutdown_artifact_paths = [os.path.join('public', 'logs', log_file)
-                                               for log_file in ['chain_of_trust.log', 'live_backing.log']]
+                                               for log_file in ['live_backing.log']]
                     artifacts_paths = [path for path in shutdown_artifact_paths
                                        if os.path.isfile(os.path.join(context.config['artifact_dir'], path))]
                     status = STATUSES['worker-shutdown']