You can turn on/off the pop-up notification using the menu bar View > Desktop Preferences menu sequence and selecting Setting the Desktop Preferences.TradeStation Help
Trade history downloads may occur when the platform detects missing order history since a previous logon or when you update to a new version of TradeStation. This process occurs automatically and may take several minutes if you have a large number of accounts and/or orders. During the download process, you will not have access to historical trade information in the TradeManager
When the trade history download begins, a progress icon appears on the system tray and, optionally, a pop-up notification message will appear from the system tray. Once the download process is complete the icon will disappear.
You can turn on/off the pop-up notification using the menu bar View > Desktop Preferences menu sequence and selecting Setting the Desktop Preferences.