What is assembly resolution exception?

So as question states what is assembly resolution exceptiona and why does it occur?

Sorry but this question is not about Unity but about a specific field of the .NET / Mono runtime (CLI).

Apart from that UnityAnswers is for concrete questions. If you get an assembly resolution exception you should get a stacktrace which tells you where it happend and then you know the code that is causing it.

Generally an assembly resolution exception tells you that the AppDomain is trying to localize an assembly that is in the referenced assembly list of your application or in the list of a referenced assembly, but couldn’t find the right assembly file. This is generally a sign that you’re either missing a required DLL file or it’s located at the wrong place so your application can’t find it. This exception is usually thrown if you try to load an assembly through reflection at runtime, but it may be caused by other things as well.

Without more information this is all you can get from us.