How to solve "The type x exists in both y aand z"?,How to solve "The type x exists in both y and z"

I’ve just exported as package a scene from a Unity 2019.2.17f1 project and imported it in another Unity 2019.2.17f1 project and large number of scripts deliver the following error:

Assets\Scripts\OpcUaComponents\OpcUaUtils.cs(76,16): error CS0433: The type 'NodeId' exists in both 'Opc.Ua.Core, Version=1.4.357.0, Culture=neutral, PublicKeyToken=bfa7a73c5cf4b6e8' and 'Opc.Ua.Core, Version=1.4.354.0, Culture=neutral, PublicKeyToken=null'

A script looks like this:

using Opc.Ua;
using Opc.Ua.Client;
using System.Collections.Generic;
using UnityEngine;

public class OpcUaUtils
{
 private static ReferenceDescription[] ListChildren(Session session, NodeId parentNodeId)
...
}

I would appreciate any ideas how to solve this because the other already published sollutions for similar issues didn’t work!

As you can see your project has two different versions of the same assembly. One has the version string “1.4.357.0” the other “1.4.354.0”. If you build for .NET Standard, Unity should provide the framework for you. So if you manually copied a version of the framework into your project you should remove it.

Though if you’re working on a larger project I highly recommend that you create a backup of your project before you remove anything ^^.