.NET Fusion logger: What is the difference between Default and Native Images?

Question

In the .NET fusion logger (FUSLOGVW.exe) what do the two options in the lower right of the screen do?

 Log Categories
  + Default
  + Native Images

And how can I use either one to diagnose a mixed-mode assembly problem?

Answer 1

Native images are the files generated by ngen.exe. It contains pre-compiled machine code for an assembly, so that the JIT compiler isn't needed. All .NET framework assemblies are ngen-ed. They have the .ni.dll filename extension.

You are typically not interested in them if you are trying to troubleshoot an assembly resolution problem. But you can see them getting loaded if you choose "Native Images" instead of "Default".