diff --git a/src/ot_orchestration/task_groups/gwas_catalog/batch_processing.py b/src/ot_orchestration/task_groups/gwas_catalog/batch_processing.py
index 6449c3d..72c82b1 100644
--- a/src/ot_orchestration/task_groups/gwas_catalog/batch_processing.py
+++ b/src/ot_orchestration/task_groups/gwas_catalog/batch_processing.py
@@ -10,7 +10,6 @@
 from airflow.operators.python import get_current_context
 from airflow.utils.helpers import chain
 from ot_orchestration.utils import create_batch_job, create_task_spec
-from ot_orchestration.utils import GCSPath
 from airflow.models import TaskInstance
 import logging
 import time
@@ -23,8 +22,10 @@ def gwas_catalog_batch_processing() -> None:
     @task(task_id="get_manifests_from_preparation", multiple_outputs=True)
     def get_batch_task_inputs(
         task_instance: TaskInstance | None = None,
-    ) -> list[GCSPath]:
+    ) -> dict[str, str]:
         """Get manifests from preparation step."""
+        if task_instance is None:
+            raise ValueError("Task instance is None")
         manifest_paths = task_instance.xcom_pull(
             task_ids="manifest_preparation.choose_manifest_paths"
         )
@@ -38,9 +39,7 @@ def get_batch_task_inputs(
     batch_inputs = get_batch_task_inputs()
 
     @task(task_id="batch_job", multiple_outputs=True)
-    def execute_batch_job(
-        manifest_paths: list[str], config_path: str
-    ) -> CloudBatchSubmitJobOperator:
+    def execute_batch_job(manifest_paths: list[str], config_path: str):
         """Create a harmonisation batch job."""
         params = get_step_params("batch_processing")
         logging.info("PARAMS: %s", params)
diff --git a/src/ot_orchestration/task_groups/gwas_catalog/manifest_preparation.py b/src/ot_orchestration/task_groups/gwas_catalog/manifest_preparation.py
index 58b9d2c..a20107f 100644
--- a/src/ot_orchestration/task_groups/gwas_catalog/manifest_preparation.py
+++ b/src/ot_orchestration/task_groups/gwas_catalog/manifest_preparation.py
@@ -3,7 +3,7 @@
 from airflow.decorators import task, task_group
 from airflow.providers.google.cloud.operators.gcs import GCSListObjectsOperator
 from ot_orchestration.types import Manifest_Object
-from ot_orchestration.utils import GCSIOManager, get_step_params, get_full_config
+from ot_orchestration.utils import IOManager, get_step_params, get_full_config
 from airflow.models.baseoperator import chain
 from ot_orchestration.utils.manifest import extract_study_id_from_path
 from airflow.utils.edgemodifier import Label
@@ -57,6 +57,8 @@ def get_new_sumstat_paths(
 def collect_sumstats_and_generate_new_manifests(
     ti: TaskInstance | None = None,
 ) -> list[Manifest_Object]:
+    if ti is None:
+        raise ValueError("Task instance is None")
     task_id: str = ti.xcom_pull(task_ids="manifest_preparation.get_execution_mode")
     logging.info("TASK ID: %s", task_id)
     new_sumstats = ti.xcom_pull(task_ids=task_id)
@@ -97,6 +99,8 @@ def amend_curation_metadata(new_manifests: list[Manifest_Object]):
     params = get_step_params("manifest_preparation")
     logging.info("USING FOLLOWING PARAMS: %s", params)
     curation_path = params["manual_curation_manifest"]
+    if not isinstance(curation_path, str):
+        raise ValueError("Curation path is not a string")
     logging.info("CURATING MANIFESTS WITH: %s", curation_path)
     curation_df = pd.read_csv(curation_path, sep="\t").drop(
         columns=["publicationTitle", "traitFromSource", "qualityControl"]
@@ -116,18 +120,20 @@ def amend_curation_metadata(new_manifests: list[Manifest_Object]):
 def read_manifests(manifest_paths: list[str]) -> list[Manifest_Object]:
     """Read manifests."""
     manifest_paths = [f"gs://{path}" for path in manifest_paths]
-    return GCSIOManager().load_many(manifest_paths)
+    return IOManager().load_many(manifest_paths)
 
 
 @task(task_id="save_config")
 def save_config(task_instance: TaskInstance | None = None) -> str:
     """Save configuration for batch processing."""
+    if task_instance is None:
+        raise ValueError("Task instance is None")
     run_id = task_instance.run_id
     params = get_step_params("manifest_preparation")
     full_config = get_full_config().serialize()
     config_path = f"gs://{params['staging_bucket']}/{params['staging_prefix']}/{run_id}/config.yaml"
     logging.info("DUMPING CONFIG TO THE FOLLOWING PATH: %s", config_path)
-    GCSIOManager().dump(gcs_path=config_path, data=full_config)
+    IOManager().resolve(config_path).dump(full_config)
     return config_path
 
 
@@ -137,6 +143,8 @@ def save_config(task_instance: TaskInstance | None = None) -> str:
 )
 def choose_manifest_paths(ti: TaskInstance | None = None) -> list[str]:
     """Choose manifests to pass to the next."""
+    if ti is None:
+        raise ValueError("Task instance is None")
     task_id: str = ti.xcom_pull(task_ids="manifest_preparation.get_execution_mode")
     logging.info("TASK ID: %s", task_id)
     if not task_id.endswith("read_manifests"):
@@ -150,7 +158,7 @@ def save_manifests(manifests: list[Manifest_Object]) -> list[Manifest_Object]:
     """Write manifests to persistant storage."""
     manifest_paths = [manifest["manifestPath"] for manifest in manifests]
     logging.info("MANIFEST PATHS: %s", manifest_paths)
-    GCSIOManager().dump_many(manifests, manifest_paths)
+    IOManager().dump_many(manifests, manifest_paths)
     return manifests
 
 
@@ -164,7 +172,6 @@ def exit_when_no_new_sumstats(new_sumstats: dict[str, str]) -> bool:
 @task_group(group_id=TASK_GROUP_ID)
 def gwas_catalog_manifest_preparation():
     """Prepare initial manifest."""
-
     fetch_existing_manifests = GCSListObjectsOperator(
         task_id="list_existing_manifests",
         bucket="{{ params.steps.manifest_preparation.staging_bucket }}",