ildasm.exe wont work

Question

ildasm.exe wont work

Maksim Maksim 31

Hello!
Can somebody help me maybe, I'm trying to use ildasm.exe just to open a simple program Hello World, written on C# in visual studio 2019.
Every time I'm getting the error "Has no valid CLR header and cannot be disassembled".

Have already googled this problem, but didn't found any solution.

Xingyu Zhao-MSFT 5,371 Reputation points

2021-04-26T06:28:42.847+00:00

Hi @Maksim Maksim ,
What's the framework version of your program?
Could you provide your Hello World program code here? It will help us make a test.
We are waiting for your update.

Maksim Maksim 31

Framework .NET 5.0

using System;

namespace sil5
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
        }
    }
}

Xingyu Zhao-MSFT 5,371 Reputation points

2021-05-11T07:14:47.847+00:00

Hi @Maksim Maksim ,
May I know whether your issue has been solved or not? If not, please share it in here.
Prajval Gahine 0 Reputation points

2023-09-02T10:46:51.2+00:00
@maksimmaksim-2485 hi,

I have similar code structure in VS. When I build my solution, it creates .dll as well as .exe file in net6.0 folder.

I am able to diassemble the native code to assembly using "> ildasm /out=HelloWorld.il HelloWorld.dll" command. => it generated two files 1. HelloWorld.il and 2. HelloWorld.res

But why I was intended to get back HelloWorld.exe from the .il code using:

"> ilasm HelloWorld.il" or "> ilasm /resource=HelloWorld.res HelloWorld.il"

I am getting HelloWorld.exe, but throw an error when run, here the error:

Unhandled Exception: System.IO.FileNotFoundException: Could not load file or assembly 'System.Runtime, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.

In nutshell I am not able to perform the round trip, i.e. from machine code to .il to again machine code.

2 answers

Your answer

Xingyu Zhao-MSFT 5,371 Reputation points

2021-04-26T06:28:42.847+00:00

Hi @Maksim Maksim ,
What's the framework version of your program?
Could you provide your Hello World program code here? It will help us make a test.
We are waiting for your update.
Maksim Maksim 31 Reputation points

2021-05-01T08:35:48.603+00:00

Framework .NET 5.0

using System; namespace sil5 { class Program { static void Main(string[] args) { Console.WriteLine("Hello World!"); } } }
Xingyu Zhao-MSFT 5,371 Reputation points

2021-05-11T07:14:47.847+00:00

Hi @Maksim Maksim ,
May I know whether your issue has been solved or not? If not, please share it in here.
Prajval Gahine 0 Reputation points

2023-09-02T10:46:51.2+00:00

@maksimmaksim-2485 hi,

I have similar code structure in VS. When I build my solution, it creates .dll as well as .exe file in net6.0 folder.

I am able to diassemble the native code to assembly using "> ildasm /out=HelloWorld.il HelloWorld.dll" command. => it generated two files 1. HelloWorld.il and 2. HelloWorld.res

But why I was intended to get back HelloWorld.exe from the .il code using:

"> ilasm HelloWorld.il" or "> ilasm /resource=HelloWorld.res HelloWorld.il"

I am getting HelloWorld.exe, but throw an error when run, here the error:

Unhandled Exception: System.IO.FileNotFoundException: Could not load file or assembly 'System.Runtime, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.

In nutshell I am not able to perform the round trip, i.e. from machine code to .il to again machine code.

Answer 1

Xingyu Zhao-MSFT 5,371

Hi @Maksim Maksim ,
In my test(.NET 5):

namespace ConsoleApp_hello  
{  
    class Program  
    {  
        static void Main(string[] args)  
        {  
            Console.WriteLine("Hello World!");  
        }  
    }  
}

When using 'ildasm.exe', you need to open '....dll' instead of '....exe'.

Hope it could be helpful.

Best Regards,
Xingyu Zhao
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Abdellah Mesquine 0 Reputation points

2024-08-16T07:56:08.5066667+00:00

Thank you Xingyu Zhao, it works!

Answer 2

LectoreVoC 1

Hey, if ildasm.exe doesn't work try write ".dll" instead ".exe".

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ildasm.exe wont work

2 answers

Your answer