To address the issue of downloading futures data from Interactive Brokers (IBKR) using QuantConnect on a Mac, ensure the following steps are correctly implemented:

1. Verify IB Gateway Path: Execute the following Python code to verify if the IB Gateway path on your system matches the expected path. Adjust the path if necessary.

    import os
    def check_ib_gateway_path():
        expected_path = '/Users/user/Applications/IB Gateway 10.30'
        if os.path.exists(expected_path):
            return "IB Gateway path exists."
        else:
            return "IB Gateway path does not exist, please check the path."
    print(check_ib_gateway_path())

2. Ensure Correct API Credentials: Double-check that your Interactive Brokers API credentials, such as client ID, username, and password, have been inputted correctly into your QuantConnect Brokerage settings.

3. Review and Configure IB Gateway Settings: Verify the configuration of your IB Gateway settings. Make sure that the socket port and connection settings align with the requirements specified by QuantConnect.

4. Log and Troubleshoot: Inspect log files within QuantConnect for detailed error messages related to the download process. The messages can facilitate pinpointing the exact cause of the failure.

5. Keep Software Updated: Ensure that both the IB Gateway and QuantConnect platform are updated to the latest versions. Compatibility can be an issue if either end is out of date.

If you continue to experience problems even after following these steps, reaching out to QuantConnect support with specific error logs would be more effective for a targeted resolution.

Sources: Interactive Brokers - QuantConnect.com