diff --git a/src/clusterfuzz/_internal/bot/tasks/setup.py b/src/clusterfuzz/_internal/bot/tasks/setup.py
index e1e6e1d5275..81492530ca1 100644
--- a/src/clusterfuzz/_internal/bot/tasks/setup.py
+++ b/src/clusterfuzz/_internal/bot/tasks/setup.py
@@ -593,6 +593,9 @@ def preprocess_update_fuzzer_and_data_bundles(
   if not fuzzer:
     logs.error('No fuzzer exists with name %s.' % fuzzer_name)
     raise errors.InvalidFuzzerError
+  if not fuzzer.blobstore_key:
+    logs.error(f'Fuzzer {fuzzer_name} does not have a blobstore_key.')
+    raise errors.InvalidFuzzerError
 
   update_input = uworker_msg_pb2.SetupInput(  # pylint: disable=no-member
       fuzzer_name=fuzzer_name,
diff --git a/src/clusterfuzz/_internal/bot/tasks/utasks/fuzz_task.py b/src/clusterfuzz/_internal/bot/tasks/utasks/fuzz_task.py
index 3d979d852ce..3b24aaa48ca 100644
--- a/src/clusterfuzz/_internal/bot/tasks/utasks/fuzz_task.py
+++ b/src/clusterfuzz/_internal/bot/tasks/utasks/fuzz_task.py
@@ -29,6 +29,7 @@
 from google.cloud import ndb
 
 from clusterfuzz._internal.base import dates
+from clusterfuzz._internal.base import errors
 from clusterfuzz._internal.base import utils
 from clusterfuzz._internal.bot import testcase_manager
 from clusterfuzz._internal.bot.fuzzers import builtin
@@ -1216,15 +1217,15 @@ def write_crashes_to_big_query(group, newly_created_testcase, existing_testcase,
       # Happens in case the big query function is disabled (local development).
       return
 
-    errors = result.get('insertErrors', [])
-    failed_count = len(errors)
+    insert_errors = result.get('insertErrors', [])
+    failed_count = len(insert_errors)
 
     monitoring_metrics.BIG_QUERY_WRITE_COUNT.increment_by(
         row_count - failed_count, {'success': True})
     monitoring_metrics.BIG_QUERY_WRITE_COUNT.increment_by(
         failed_count, {'success': False})
 
-    for error in errors:
+    for error in insert_errors:
       logs.error(
           ('Ignoring error writing the crash '
            f'({group.crashes[error["index"]].crash_type}) to BigQuery.'),
@@ -2290,7 +2291,11 @@ def utask_preprocess(fuzzer_name, job_type, uworker_env):
   # Delay adding the fuzz target to logs context until it is chosen in
   # preprocess.
   with logs.fuzzer_log_context(fuzzer_name, job_type, fuzz_target=None):
-    return _utask_preprocess(fuzzer_name, job_type, uworker_env)
+    try:
+      return _utask_preprocess(fuzzer_name, job_type, uworker_env)
+    except errors.InvalidFuzzerError:
+      logs.error('Fuzzer %s is invalid or no longer exists.' % fuzzer_name)
+      return None
 
 
 def save_fuzz_targets(output):
diff --git a/src/clusterfuzz/_internal/tests/core/bot/tasks/setup_test.py b/src/clusterfuzz/_internal/tests/core/bot/tasks/setup_test.py
index 6e39dbe6b1c..f7dbe70daae 100644
--- a/src/clusterfuzz/_internal/tests/core/bot/tasks/setup_test.py
+++ b/src/clusterfuzz/_internal/tests/core/bot/tasks/setup_test.py
@@ -222,7 +222,10 @@ def setUp(self):
     self.fuzzer_name = 'fuzzer'
     data_bundle_name = 'data_bundle_name'
     data_types.Fuzzer(
-        name=self.fuzzer_name, data_bundle_name=data_bundle_name).put()
+        name=self.fuzzer_name,
+        data_bundle_name=data_bundle_name,
+        blobstore_key='blobstore_key',
+    ).put()
     self.data_bundle = data_types.DataBundle(name=data_bundle_name)
     self.data_bundle.put()
     data_types.DataBundle(name=data_bundle_name).put()