Import failed. The NinjaScript Archive File may contain duplicate method names that already exist on your PC...

Initial Steps

When the import fails using the standard methods of installing or updating the NinjaScript add-on, then we can try new alternatives, among them manually importing the NinjaScript add-on.

To install manually as alternative, follow the steps below:

• Close Ninjatrader.
• Open the downloaded zip file from our website ProductName-1.X.X.X-xxxxx.zip and copy the ProductName.dll (all .dlls files) file(s) to the location in your computer \Documents\Ninjatrader 8\bin\Custom, click Yes to replace the old file.
• Open Ninjatrader and click Yes to all warning messages.
• Check if you have the latest Product version.

The product is ready to use. Please also make sure that you are not using Microsoft OneDrive with NinjaTrader, as they are incompatible. NinjaTrader and OneDrive Compatibility: A Comprehensive Guide.

Extra Steps

Almos sure you are using Microsoft's OneDrive, which is incompatible with NinjaTrader. If this is the case, we would like to invite you to check out our related post via this link and contact NinjaTrader support to resolve the incompatibility issue between OneDrive and NinjaTrader.

For the best assistance, I kindly recommend contacting their support team at support@ninjatrader.com. They are well-equipped to help you resolve this issue.