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Editorial Team
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Asked: 2026-05-13T17:35:57+00:00

How do I determine if the Native images are being used without the Loader

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How do I determine if the Native images are being used without the Loader verifing the signature of the assembly at runtime, or even using the GAC’ed assembly?

I have complex system that we’re experimenting with NGen but currently we’re running the exe from the folder where all the DLL’s are located due to a lot of late binding dependencies, looking at Process Explorer, it looks like the Native images are being used, but how can I be sure I’m getting the full benefit and eliminating the Loader Verification step?

Cheers,
Graeme.

Update:
I’m getting lots of this sort of thing from the Assembly Binding Log viewer:

LOG: [Level 1]Start validating IL dependency MyCompany.Entities, Version=2.0.0.0, Culture=neutral, PublicKeyToken=7cd8595f4671c5dd.
LOG: Dependency evaluation succeeded.

and at the end 

LOG: Validation of dependencies succeeded.
LOG: Start loading all the dependencies into load context.
LOG: Loading of dependencies succeeded.
LOG: Bind to native image succeeded.
Native image has correct version information.
Attempting to use native image C:\Windows\assembly\NativeImages_v2.0.50727_32\MyCompany.Mylibrary#\4710bb8309419d707681bd360088181f\MyCompany.MyLibrary.MyClass.ni.dll.
ZAP: Native image has been relocated.
Native image successfully used.

So it’s using the Native images but still verifying them, i.e. not using the GAC version even though that’s where I created the Native image from, Like so:

ngen install "MyCompany.Entites, Version=2.0.0.0, Culture=neutral, PublicKeyToken=7cd8595f4671c5dd, processorArchitecture=MSIL"

Footnote:
This articles seems to imply that if the assemblies are not loaded from the GAC then the verification process will offset the NGen advantages?
CLR Inside Out – Improving Application Startup Performance (MSDN)

Update – As Nobugz has pointed out in a comment below, the verification step mentioned above is not performed since 3.5 SP1 see:MSDN Docs on NGen

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1 Answer

  1. Editorial Team

    You can easily see it from the Fuslogvw.exe tool. Start it from the Visual Studio Command Prompt. Configure it with Log Categories = Native Images, Settings + Log all binds to disk. Run your program. Back to fuslogvw, Refresh. It will show you a list of all assemblies that got loaded.

    Double-click an entry to see how the assembly got loaded. If it came from the GAC, you’ll see:

    LOG: IL assembly loaded from C:\Windows\assembly\GAC_MSIL\blahblah

    If the Ngen-ed images was used, you’ll see:

    LOG: Bind to native image succeeded.

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