Frozen orders can occur on simulated accounts– it does not happen on live accounts. You can reset the simulated account to clear these orders. In the NinjaTrader Control Center, Accounts Tab, select the account that has the locked orders. Right click on this account and click “Edit Account…” and in the Properties area, click “reset” and make sure Clear History is checked, then click Yes. The NinjaTrader 8 platform may seem like it is frozen, but wait and it will successfully complete the process. You can also remove the orders, without resetting account performance history. In the NinjaTrader Control Center, Tools Menu, select Database Management. In the Database window, select Reset DB, and make sure only Historical orders is selected, and hit the Reset button.