Could not load file or assembly … An attempt was m

Question

I have two projects, ProjectA and ProjectB. ProjectB is a console application, which depends on ProjectA. Yesterday, everything was working fine, but suddenly today when I run ProjectB I get this:

BadImageFormatException was unhandled:
Could not load file or assembly 'ProjectA, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. An attempt was made to load a program with an incorrect format.

Both are just regular projects, with no dependencies on any other non-.Net projects. Both are fully .Net - there is no native code, and no P/Invoke. I have other projects which depend on ProjectA and still work just fine.

Things I have tried:

• Make sure both projects are set to "Any CPU," with the build checkbox checked. They are.
• Make sure both projects are for the same Target Framework (.Net 4.0 Client Profile).
• Under ProjectB --> References --> ProjectA --> Properties, make sure "Copy Local" is set to "True" _ (I verified that ProjectA.dll is being copied correctly)
• Clean/Rebuild the solution. I even tried manually deleting the /bin and /obj folders in both projects.
• Restart Visual Studio. Restart my computer.
• Check out an entirely new copy of the repository.

But I still get the same error. I have no idea what I did to cause this, nor how to fix it. Any ideas?

Answer 1

I had this problem running unit tests (xunit) in Visual Studio 2015 and came across the following fix:

Menu Bar -> Test -> Test Settings -> Default Processor Architecture -> X64

Answer 2

The Chilkat .NET 4.5 assembly requires the VC++ 2012 or 2013 runtime to be installed on any computer where your application runs. Most computers will already have it installed. Your development computer will have it because Visual Studio has been installed. However, if deploying to a computer where the required VC++ runtime is not available, the above error will occur:

Install all of the bellow packages

Visual C++ Redistributable Packages for Visual Studio 2013 - vcredist_x64

Visual C++ Redistributable Packages for Visual Studio 2013 - vcredist_x86

Visual C++ Redistributable Packages for Visual Studio 2012 - vcredist_x64

Visual C++ Redistributable Packages for Visual Studio 2012 - vcredist_x86

Answer 3

In my case a dependency was missing in the dll that threw this exception. I checked with Dependency Walker, added the missing dll and the problem was resolved.

More specifically, I somehow corrupted my opencv_core340.dll by accidentally adding SVN keywords to it, and thus my dll could no longer use it. However I don't believe that the solution to this problem depends on whether the dll is corrupted or missing. I'm just adding this for the sake of giving complete information.

Answer 4

Might be you are facing the problem with your website after deploying on server.

Then you need to adjust your application pool to Enable 32-Bit Applications.

Steps:

1. Open IIS Manager
2. Click on Application Pools
3. Select whatever application pool you are using
4. From right pane, click Advanced Settings...
5. Set Enable 32-Bit Applications to True

Answer 5

If you use LibreOffice from your program via cli .net integration like me, I got the same error. I use the older version of LibreOffice on the production environment on my PC I installed a newer version that was in conflict. Just uninstall LibreOffice. I found the solution here .NET CLI: Could not load file or assembly 'cli_cppuhelper'

Answer 6

I also face this problem in a project, after a few minutes i found the solution, this problem is due to CPU configuration, If you are using Visual Studio 2010 or VS 2013, just goto project 's properties and then select Compile from side bar and there will be 5 drop-down, 5th Drop-down will be Target CPU:, you should set it to x86 or x64 according to your requirements instead of Any CPU.

My problem was solved after changing it to x86.