diff --git a/python/graphstorm/sagemaker/sagemaker_gb_convert.py b/python/graphstorm/sagemaker/sagemaker_gb_convert.py
index 9716b90c2..337a9400d 100644
--- a/python/graphstorm/sagemaker/sagemaker_gb_convert.py
+++ b/python/graphstorm/sagemaker/sagemaker_gb_convert.py
@@ -19,6 +19,7 @@
 import logging
 import os
 import time
+from collections import defaultdict
 from packaging import version
 
 import boto3
@@ -59,7 +60,7 @@ def run_gb_convert(s3_output_path: str, local_dist_part_config: str, njobs: int)
             f"but DGL version was {dgl_version}. "
         )
 
-    boto_session = boto3.Session(region_name=os.environ['AWS_REGION'])
+    boto_session = boto3.Session(region_name=os.environ["AWS_REGION"])
     sagemaker_session = sagemaker.Session(boto_session=boto_session)
 
     # Run the actual conversion, this will create the fused_csc_sampling_graph.pt
@@ -71,25 +72,41 @@ def run_gb_convert(s3_output_path: str, local_dist_part_config: str, njobs: int)
     # Iterate through the partition data and upload only the modified/new
     # files to the corresponding path on S3
     upload_start = time.time()
+    fused_files_exist = defaultdict(lambda: False)
     for root, _, files in os.walk(os.path.dirname(local_dist_part_config)):
         for file in files:
-            if file.endswith(("fused_csc_sampling_graph.pt", ".json")):
+            if file.endswith("fused_csc_sampling_graph.pt"):
+                partition_id = root.split("/")[-1]
+                # Set fused file existence to true for this partition
+                fused_files_exist[partition_id] = True
+                # Partition data need to be uploaded to partition-id dirs
+                s3_path = os.path.join(s3_output_path, f"{partition_id}")
+            elif file.endswith(".json"):
+                # Partition output metadata file needs to be uploaded to root dir
+                s3_path = s3_output_path
+            else:
+                # We skip other files
                 partition_id = root.split("/")[-1]
                 if "part" in partition_id:
-                    # Partition data need to be uploaded to partition-id dirs
-                    assert file.endswith("fused_csc_sampling_graph.pt")
-                    s3_path = os.path.join(s3_output_path, f"{partition_id}")
-                else:
-                    # Metadata file needs to be uploaded to root dir
-                    assert file.endswith(".json")
-                    s3_path = s3_output_path
-                logging.info(
-                    "Uploading local %s to %s",
-                    os.path.join(root, file),
-                    s3_path)
-                S3Uploader.upload(
-                    local_path=os.path.join(root, file),
-                    desired_s3_uri=s3_path,
-                    sagemaker_session=sagemaker_session
-                )
+                    # Set file existence to False only if
+                    # we haven't encountered a fused file already
+                    fused_files_exist[partition_id] = (
+                        False or fused_files_exist[partition_id]
+                    )
+                continue
+
+            logging.info("Uploading local %s to %s", os.path.join(root, file), s3_path)
+            S3Uploader.upload(
+                local_path=os.path.join(root, file),
+                desired_s3_uri=s3_path,
+                sagemaker_session=sagemaker_session,
+            )
+
+    for partition_id, fused_file_exists in fused_files_exist.items():
+        if not fused_file_exists:
+            raise RuntimeError(
+                f"Partition {partition_id} did not have "
+                "a fused_csc_sampling_graph.pt file."
+            )
+
     logging.info("Uploading took %f sec.", time.time() - upload_start)