microsoft/qlib · error · ValueError

User {} has been loaded

Error message

User {} has been loaded

What it means

Raised by UserManager.create_user (qlib/contrib/online/manager.py) when trying to load a user whose user_id is already present in the in-memory self.users dict. The manager refuses to load the same online-user twice to avoid duplicate accounts/strategies being tracked under one id.

Source

Thrown at qlib/contrib/online/manager.py:68

        self.users = {}
        self.user_record = pd.read_csv(self.users_file, index_col=0)
        for user_id in self.user_record.index:
            self.users[user_id] = self.load_user(user_id)

    def load_user(self, user_id):
        """
        return a instance of User() represents a user to be processed
            Parameter
                user_id : string
            :return
                user : User()
        """
        account_path = self.data_path / user_id
        strategy_file = self.data_path / user_id / "strategy_{}.pickle".format(user_id)
        model_file = self.data_path / user_id / "model_{}.pickle".format(user_id)
        cur_user_list = list(self.users)
        if user_id in cur_user_list:
            raise ValueError("User {} has been loaded".format(user_id))
        else:
            trade_account = Account(0)
            trade_account.load_account(account_path)
            strategy = load_instance(strategy_file)
            model = load_instance(model_file)
            user = User(account=trade_account, strategy=strategy, model=model)
            return user

    def save_user_data(self, user_id):
        """
        save a instance of User() to user data path
            Parameter
                user_id : string
        """
        if not user_id in self.users:
            raise ValueError("Cannot find user {}".format(user_id))
        self.users[user_id].account.save_account(self.data_path / user_id)
        save_instance(

View on GitHub (pinned to 79633dd950)

Solutions

1. Skip creation if the user already exists: check `user_id in um.users` before calling create_user.
2. Use a unique user_id for each new online user.
3. If the existing entry is stale, call um.remove_user(user_id) (and reload) before creating it again.

Example fix

# before
um.load_users()
user = um.create_user("u1")  # ValueError: User u1 has been loaded

# after
um.load_users()
if "u1" not in um.users:
    user = um.create_user("u1")

if user_id in um.users:
    user = um.users[user_id]
else:
    user = um.create_user(user_id)

def user_loaded(um, user_id) -> bool:
    return user_id in um.users

When it happens

Trigger: Calling um.load_users() (which loads all recorded users) and then um.create_user(user_id) for an id already in users_file; or calling create_user twice with the same user_id in one session.

Common situations: An online-serving script that both bulk-loads users and re-adds one explicitly; retrying a failed setup script without restarting the UserManager; id collisions because user ids are derived from timestamps or counters that repeat.

Related errors

• Cannot find user {}
• User data for {} already exists
• Cannot find user data {}
• model is not fitted yet!
• model is not fitted yet!

AI-assisted analysis of microsoft/qlib@79633dd950 (2026-08-15). Data as JSON: /api/errors/62a68ce6e2b73098. Report an issue: GitHub.