diff --git a/src/onc/modules/_OncArchive.py b/src/onc/modules/_OncArchive.py
index 567fb4a..3b96675 100644
--- a/src/onc/modules/_OncArchive.py
+++ b/src/onc/modules/_OncArchive.py
@@ -112,7 +112,7 @@ def downloadDirectArchivefile(
             filePath = outPath / filename
             fileExists = os.path.exists(filePath)
 
-            if not fileExists or overwrite:
+            if not fileExists or os.path.getsize(filePath) == 0 or overwrite:
                 print(f'   ({tries} of {n}) Downloading file: "{filename}"')
                 downInfo = self.downloadArchivefile(filename, overwrite)
                 size += downInfo["size"]
diff --git a/src/onc/modules/_util.py b/src/onc/modules/_util.py
index f8c3720..37c1a8c 100644
--- a/src/onc/modules/_util.py
+++ b/src/onc/modules/_util.py
@@ -1,3 +1,4 @@
+import os
 import time
 from datetime import timedelta
 from pathlib import Path
@@ -17,16 +18,15 @@ def saveAsFile(
     filePath = outPath / fileName
     outPath.mkdir(parents=True, exist_ok=True)
 
-    # Save file in outPath if it doesn't exist yet
-    if Path.exists(filePath) and not overwrite:
+    # Save/Overwrite file in outPath if the file doesn't exist yet
+    # or it is there but with 0 file size
+    if not overwrite and Path.exists(filePath) and os.path.getsize(filePath) != 0:
         raise FileExistsError(filePath)
 
     start = time.time()
     size = 0
-    with open(filePath, "wb+") as file:
-        for chunk in response.iter_content(chunk_size=128):
-            file.write(chunk)
-            size += len(chunk)
+    with open(filePath, "wb") as file:
+        file.write(response.content)
 
     downloadTime = time.time() - start
     return (size, round(downloadTime, 3))
diff --git a/src/onc/onc.py b/src/onc/onc.py
index 2aa8300..830879a 100644
--- a/src/onc/onc.py
+++ b/src/onc/onc.py
@@ -1319,7 +1319,8 @@ def downloadArchivefile(self, filename: str = "", overwrite: bool = False):
         filename : str, default ""
             A valid name of a file in DMAS Archiving System.
         overwrite : bool, default False
-            Whether to overwrite the file if it exists.
+            Whether to overwrite the file if it exists. 0 size file is treated as non-existent,
+            meaning it gets overwritten even when overwrite=False.
 
         Returns
         -------
diff --git a/tests/archive_file/conftest.py b/tests/archive_file/conftest.py
index dba05d7..273ae56 100644
--- a/tests/archive_file/conftest.py
+++ b/tests/archive_file/conftest.py
@@ -18,3 +18,9 @@ def params_location():
 def params_location_multiple_pages(params_location):
     # rowLimit should be less than the total number of rows.
     return params_location | {"rowLimit": 2}
+
+
+@pytest.fixture
+def params_location_single_file(params_location):
+    # Returned archivefile name should be BPR-Folger-59_20191126T000000.000Z.txt
+    return params_location | {"dateFrom": "2019-11-26", "dateTo": "2019-11-27"}
diff --git a/tests/archive_file/test_archivefile_direct_download.py b/tests/archive_file/test_archivefile_direct_download.py
index 36501e6..59b062e 100644
--- a/tests/archive_file/test_archivefile_direct_download.py
+++ b/tests/archive_file/test_archivefile_direct_download.py
@@ -1,3 +1,6 @@
+import os
+
+
 def test_valid_params_one_page(requester, params_location, util):
     data = requester.getArchivefile(params_location)
     result = requester.downloadDirectArchivefile(params_location)
@@ -16,3 +19,24 @@ def test_valid_params_multiple_pages(requester, params_location_multiple_pages,
     )
 
     assert result["stats"]["fileCount"] == params_location_multiple_pages["rowLimit"]
+
+
+def test_valid_params_overwrite_zero_file_size(
+    requester, params_location_single_file, util
+):
+    filename = "BPR-Folger-59_20191126T000000.000Z.txt"
+
+    file_path = requester.outPath / filename
+
+    # Touch an empty file
+    with open(file_path, "w"):
+        pass
+
+    # Case when downloading failed, leaving an empty file behind
+    assert os.path.getsize(file_path) == 0
+
+    requester.downloadDirectArchivefile(params_location_single_file, overwrite=False)
+
+    assert (
+        os.path.getsize(file_path) != 0
+    ), "0-size file should be overwritten even if overwrite is False"
diff --git a/tests/archive_file/test_archivefile_download.py b/tests/archive_file/test_archivefile_download.py
index f61b449..8ae6c9b 100644
--- a/tests/archive_file/test_archivefile_download.py
+++ b/tests/archive_file/test_archivefile_download.py
@@ -1,3 +1,5 @@
+import os
+
 import pytest
 import requests
 
@@ -25,3 +27,22 @@ def test_valid_params(requester, util):
     requester.downloadArchivefile(filename, overwrite=True)
 
     assert util.get_download_files_num(requester) == 1
+
+
+def test_valid_params_overwrite_zero_file_size(requester):
+    filename = "BPR-Folger-59_20191123T000000.000Z.txt"
+
+    file_path = requester.outPath / filename
+
+    # Touch an empty file
+    with open(file_path, "w"):
+        pass
+
+    # Case when downloading failed, leaving an empty file behind
+    assert os.path.getsize(file_path) == 0
+
+    requester.downloadArchivefile(filename, overwrite=False)
+
+    assert (
+        os.path.getsize(file_path) != 0
+    ), "0-size file should be overwritten even if overwrite is False"