Message on the screen:

"Error has occurred in NinjaTrader database cache. Close NinjaTrader and delete 'Documents\NinjaTrader 8\db\cache' folder."


Solution:

  1. Close NinjaTrader. Delete 'Documents\NinjaTrader 8\db\cache' folder. If this didn't help see #2.
  2. Close NinjaTrader. Delete 'Documents\NinjaTrader 8\db' folder. You will lose all loaded market data. Backup this folder before deleting. NinjaTrader 8 will re-create \db folder on the next run.