Your duplicate question on StackOverflow:
https://stackoverflow.com/q/29239000/850848

My answer was:

It looks like you are publishing your application with a different version of the assembly, than you have built the application against.

The WinSCP .NET assembly version 1.0.6.3261 comes with WinSCP 5.1.5.

I suggest you remove all references to WinSCP from your project, delete all copies of the assembly, and reinstall the assembly from NuGet.

Then make sure that:

- In Solution Explorer, the Copy Local property is set to True for WinSCPnet.dll
- In Project properties, go to Publish page, click Application Files and make sure that Publish Status is set to Include for WinSCPnet.dll

(though these should be defaults, when installing the assembly from NuGet)

From what I have used so far this is a great tool.

Added WinSCP to my C# project using nugget (which is marked as version 5.7).

Examples given are concise and had all the options working in no time at all.

I have finished my app and created a deployment package.

Anyway down to my problem.

When I try and deploy the package onto a Windows 2012 Server I get the following error:

"Unable to install or run the application. The application requires that assembly WinSCP Version 1.0.6.3261 be installed in the Global Assembly Cache (GAC) first."

On checking the version of WinSCPnet.dll that came as part of the deployment is 1.2.6.5125.

Anyway, I have added this version to my GAC using gacutil.exe, but the above error is shown again

I have manually added into the GAC the version of the WinSCPnet.dll that came with the nugget package which is version 1.2.6.5125.

On re-running the deployment, the same message is still displayed.

What have I done wrong?

Paul