diff --git a/gdc_client/upload/client.py b/gdc_client/upload/client.py
index 77e6247..1c413d4 100644
--- a/gdc_client/upload/client.py
+++ b/gdc_client/upload/client.py
@@ -5,19 +5,18 @@
 import os
 import platform
 import random
-import requests
 import time
-import yaml
-
 from collections import deque
 from concurrent.futures import ThreadPoolExecutor, as_completed
-from gdc_client.parcel.utils import tqdm, tqdm_file
-from gdc_client.upload import manifest
-from lxml import etree
 from mmap import PAGESIZE, mmap
-from multiprocessing import Manager
 from urllib import parse as urlparse
 
+import requests
+import yaml
+from lxml import etree
+
+from gdc_client.parcel.utils import tqdm, tqdm_file
+from gdc_client.upload import manifest
 
 log = logging.getLogger("upload")
 
@@ -38,11 +37,6 @@
 
     from multiprocessing.pool import ThreadPool as Pool
 
-    # Fake multiprocessing manager namespace
-    class FakeNamespace(object):
-        def __init__(self):
-            self.completed = 0
-
     from mmap import ALLOCATIONGRANULARITY as PAGESIZE
     from mmap import ACCESS_READ
 
@@ -77,7 +71,6 @@ def upload_multipart(
     part_number,
     headers,
     verify=True,
-    ns=None,
     debug=False,
 ):
     tries = MAX_RETRIES
@@ -112,10 +105,6 @@ def upload_multipart(
 
             if res.status_code == 200:
                 log.debug("Finish upload part {}".format(part_number))
-
-                if ns is not None:
-                    ns.completed += 1
-
                 return True
 
             time.sleep(get_sleep_time(tries))
@@ -461,7 +450,7 @@ def multipart_upload(self):
 
                 if self.debug:
                     log.debug(
-                        "Completed: {}/{}".format(self.ns.completed, self.total_parts)
+                        "Completed: {}/{}".format(self.completed, self.total_parts)
                     )
 
                 self.complete()
@@ -525,12 +514,7 @@ def initiate(self):
 
     def upload_parts(self):
         args_list = []
-        if OS_WINDOWS:
-            self.ns = FakeNamespace()
-        else:
-            manager = Manager()
-            self.ns = manager.Namespace()
-            self.ns.completed = 0
+        self.completed = 0
 
         part_amount = int(math.ceil(self.file_size / float(self.upload_part_size)))
 
@@ -549,7 +533,6 @@ def upload_parts(self):
                         i + 1,
                         self.headers,
                         self.verify,
-                        self.ns,
                         self.debug,
                     ]
                 )
@@ -577,6 +560,7 @@ def upload_parts(self):
                 """
                 if future.result():
                     log.debug("Part: {} is done".format(part_number))
+                    self.completed += 1
                     pbar.update()
                 else:
                     log.warning("Part: {} failed".format(part_number))
@@ -596,11 +580,11 @@ def list_parts(self):
 
     def complete(self):
         self.check_multipart()
-        if self.ns.completed != self.total_parts:
+        if self.completed != self.total_parts:
             raise Exception(
                 """Multipart upload failed for file {}:
                 completed parts: {}, total parts: {}, please try to resume""".format(
-                    self.node_id, self.ns.completed, self.total_parts
+                    self.node_id, self.completed, self.total_parts
                 )
             )
 
diff --git a/tests/test_upload_client.py b/tests/test_upload_client.py
index 297acf9..30ae46b 100644
--- a/tests/test_upload_client.py
+++ b/tests/test_upload_client.py
@@ -1,18 +1,18 @@
-import boto3
-import httmock
 import json
 import os
-import pytest
 import re
-
 from collections import namedtuple
-from gdc_client.upload import client
-from lxml import etree
 from typing import Optional
 from urllib.parse import parse_qs
 from xml.etree.ElementTree import Element
+
+import boto3
+import httmock
+import pytest
+from lxml import etree
 from xmltodict import parse
 
+from gdc_client.upload import client
 
 QueryParts = namedtuple("QueryParts", field_names=["node_type", "node_id", "fields"])
 FIVE_MB = 5 * 1024 * 1024
@@ -39,14 +39,13 @@ def parse_graphql_query(query: str) -> Optional[QueryParts]:
     )
 
 
-@pytest.fixture
-def mock_simple_upload_client(mock_dir_path):
+def build_client(mock_dir_path: str, is_multipart: bool) -> client.GDCUploadClient:
     return client.GDCUploadClient(
         token="dummy",
         processes=2,
         server="localhost",
         upload_part_size=FIVE_MB,
-        multipart=False,
+        multipart=is_multipart,
         files=[
             {"id": "file-id-2", "path": mock_dir_path},
             {"id": "file-id-1", "project_id": "GDC-MISC", "path": mock_dir_path},
@@ -55,20 +54,14 @@ def mock_simple_upload_client(mock_dir_path):
     )
 
 
+@pytest.fixture
+def mock_simple_upload_client(mock_dir_path):
+    return build_client(mock_dir_path, is_multipart=False)
+
+
 @pytest.fixture
 def mock_multipart_upload_client(mock_dir_path):
-    return client.GDCUploadClient(
-        token="dummy",
-        processes=2,
-        server="localhost",
-        upload_part_size=FIVE_MB,
-        multipart=True,
-        files=[
-            {"id": "file-id-2", "path": mock_dir_path},
-            {"id": "file-id-1", "project_id": "GDC-MISC", "path": mock_dir_path},
-        ],
-        debug=False,
-    )
+    return build_client(mock_dir_path, is_multipart=True)
 
 
 @pytest.fixture