diff --git a/app/api/domains/cho.py b/app/api/domains/cho.py
index 068277f75..b7ac5b8f1 100644
--- a/app/api/domains/cho.py
+++ b/app/api/domains/cho.py
@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import asyncio
+import hashlib
 import logging
 import re
 import struct
@@ -759,12 +760,23 @@ async def handle_osu_login_request(
 
     # TODO: store adapters individually
 
+    # Some disk manufacturers set constant/shared ids for their products.
+    # In these cases, there's not a whole lot we can do -- we'll allow them thru.
+    INACTIONABLE_DISK_SIGNATURE_MD5S: list[str] = [
+        hashlib.md5(b"0").hexdigest(),  # "0" is likely the most common variant
+    ]
+
+    if login_data["disk_signature_md5"] not in INACTIONABLE_DISK_SIGNATURE_MD5S:
+        disk_signature_md5 = login_data["disk_signature_md5"]
+    else:
+        disk_signature_md5 = None
+
     hw_matches = await client_hashes_repo.fetch_any_hardware_matches_for_user(
         userid=user_info["id"],
         running_under_wine=running_under_wine,
         adapters=login_data["adapters_md5"],
         uninstall_id=login_data["uninstall_md5"],
-        disk_serial=login_data["disk_signature_md5"],
+        disk_serial=disk_signature_md5,
     )
 
     if hw_matches:
diff --git a/app/repositories/client_hashes.py b/app/repositories/client_hashes.py
index 67f3494bc..8f7d50c6c 100644
--- a/app/repositories/client_hashes.py
+++ b/app/repositories/client_hashes.py
@@ -13,6 +13,8 @@
 from sqlalchemy import select
 from sqlalchemy.dialects.mysql import Insert as MysqlInsert
 from sqlalchemy.dialects.mysql import insert as mysql_insert
+from sqlalchemy.sql import ColumnElement
+from sqlalchemy.types import Boolean
 
 import app.state.services
 from app.repositories import Base
@@ -101,8 +103,8 @@ async def create(
 async def fetch_any_hardware_matches_for_user(
     userid: int,
     running_under_wine: bool,
-    adapters: str | None = None,
-    uninstall_id: str | None = None,
+    adapters: str,
+    uninstall_id: str,
     disk_serial: str | None = None,
 ) -> list[ClientHashWithPlayer]:
     """\
@@ -119,13 +121,13 @@ async def fetch_any_hardware_matches_for_user(
     if running_under_wine:
         select_stmt = select_stmt.where(ClientHashesTable.uninstall_id == uninstall_id)
     else:
-        select_stmt = select_stmt.where(
-            or_(
-                ClientHashesTable.adapters == adapters,
-                ClientHashesTable.uninstall_id == uninstall_id,
-                ClientHashesTable.disk_serial == disk_serial,
-            ),
-        )
+        # make disk serial optional in the OR
+        oneof_filters: list[ColumnElement[Boolean]] = []
+        oneof_filters.append(ClientHashesTable.adapters == adapters)
+        oneof_filters.append(ClientHashesTable.uninstall_id == uninstall_id)
+        if disk_serial is not None:
+            oneof_filters.append(ClientHashesTable.disk_serial == disk_serial)
+        select_stmt = select_stmt.where(or_(*oneof_filters))
 
     client_hashes = await app.state.services.database.fetch_all(select_stmt)
     return cast(list[ClientHashWithPlayer], client_hashes)