How to Fix Unable to connect to DB error when starting the NinjaTrader application

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We have observed reports of users receiving an Unable to connect to DB: unable to open database file error message when starting Ninja Trader in their Windows virtual machines (VM). This issue is due to the Shared folders feature being enabled during the installation of the Ninja Trader application.

This article offers steps for a workaround to address this issue.


To resolve the issue, follow the instructions provided below:

NOTE: Re-enabling the  Mirror Mac and Windows user folders option will result in a recurrence of the Unable to connect to DB: unable to open database file error when you attempt to use the Ninja Trader application.

  1. Start Parallels Desktop.
  2. Start your Windows VM.
  3. Uninstall Ninja Trader from your Windows VM.
    • Click the Start button (Windows icon) on the screen's bottom.
    • Click on the Settings gear icon.
    • In the Settings window, click on the Apps option.
    • You'll see a list of installed applications in the Installed Apps section.
    • Scroll down or use the search bar to find Ninja Trader.
    • Click the Uninstall button below the app's name and details and follow the required steps.
    • Once done, open Windows Explorer.
    • Navigate to C:\>Program File (x86) and delete the NinjaTrader 8 folder (if it exists in that directory)
  4. Shut down the VM. Make sure that the VM is shut down. If it is suspended, please run it and then shut it down (ActionsShut Down).
  5. Open your VM's configuration.
  6. Click Options and select Sharing.
  7. Uncheck the Mirror Mac and Windows user folders option.
  8. Start the Windows VM.
  9. Reinstall and launch the NinjaTrader application.

After these actions, all applications installed inside the virtual machine will store their data inside the virtual machine, unlike when Shared Profile is enabled. This means the files you create inside the virtual machine will not be shown or accessible on your host Mac. You can continue using the Windows application to open files on the Mac side using the Open with > context menu.

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