diff --git a/api/obs/api/db.py b/api/obs/api/db.py
index 8830574..10dbbb3 100644
--- a/api/obs/api/db.py
+++ b/api/obs/api/db.py
@@ -3,7 +3,7 @@ from contextvars import ContextVar
 from contextlib import asynccontextmanager
 from datetime import datetime
 import os
-from os.path import join, dirname
+from os.path import exists, join, dirname
 from json import loads
 import re
 import math
@@ -12,6 +12,7 @@ import random
 import string
 import secrets
 from slugify import slugify
+import logging
 
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -37,6 +38,8 @@ from sqlalchemy import (
 from sqlalchemy.dialects.postgresql import HSTORE, UUID
 
 
+log = logging.getLogger(__name__)
+
 Base = declarative_base()
 
 
@@ -377,6 +380,29 @@ class User(Base):
             "image": self.image,
         }
 
+    async def rename(self, config, new_name):
+        old_name = self.username
+
+        renames = [
+            (join(basedir, old_name), join(basedir, new_name))
+            for basedir in [config.PROCESSING_OUTPUT_DIR, config.TRACKS_DIR]
+        ]
+
+        for src, dst in renames:
+            if exists(dst):
+                raise FileExistsError(
+                    f"cannot move {src!r} to {dst!r}, destination exists"
+                )
+
+        for src, dst in renames:
+            if not exists(src):
+                log.debug("Rename user %s: Not moving %s, not found", self.id, src)
+            else:
+                log.info("Rename user %s: Moving %s to %s", self.id, src, dst)
+                os.rename(src, dst)
+
+        self.username = new_name
+
 
 class Comment(Base):
     __tablename__ = "comment"
@@ -403,7 +429,10 @@ class Comment(Base):
 
 Comment.author = relationship("User", back_populates="authored_comments")
 User.authored_comments = relationship(
-    "Comment", order_by=Comment.created_at, back_populates="author", passive_deletes=True
+    "Comment",
+    order_by=Comment.created_at,
+    back_populates="author",
+    passive_deletes=True,
 )
 
 Track.author = relationship("User", back_populates="authored_tracks")
@@ -418,7 +447,10 @@ Track.comments = relationship(
 
 OvertakingEvent.track = relationship("Track", back_populates="overtaking_events")
 Track.overtaking_events = relationship(
-    "OvertakingEvent", order_by=OvertakingEvent.time, back_populates="track", passive_deletes=True
+    "OvertakingEvent",
+    order_by=OvertakingEvent.time,
+    back_populates="track",
+    passive_deletes=True,
 )
 
 
diff --git a/api/obs/api/routes/login.py b/api/obs/api/routes/login.py
index f17181c..5727b05 100644
--- a/api/obs/api/routes/login.py
+++ b/api/obs/api/routes/login.py
@@ -128,16 +128,20 @@ async def login_redirect(req):
         user = User(sub=sub, username=preferred_username, email=email)
         req.ctx.db.add(user)
     else:
-        log.info("Logged in known user (id: %s, sub: %s).", user.id, user.sub)
+        log.info(
+            "Logged in known user (id: %s, sub: %s, %s).",
+            user.id,
+            user.sub,
+            preferred_username,
+        )
 
         if email != user.email:
             log.debug("Updating user (id: %s) email from auth system.", user.id)
             user.email = email
 
-        # TODO: re-add username change when we can safely rename users
-        # if preferred_username != user.username:
-        #     log.debug("Updating user (id: %s) username from auth system.", user.id)
-        #     user.username = preferred_username
+        if preferred_username != user.username:
+            log.debug("Updating user (id: %s) username from auth system.", user.id)
+            await user.rename(req.app.config, preferred_username)
 
     await req.ctx.db.commit()
 
@@ -156,4 +160,4 @@ async def logout(req):
     auth_req = client.construct_EndSessionRequest(state=session["state"])
     logout_url = auth_req.request(client.end_session_endpoint)
 
-    return redirect(logout_url+f"&redirect_uri={req.ctx.api_url}/logout")
+    return redirect(logout_url + f"&redirect_uri={req.ctx.api_url}/logout")