NuGet: 'X' already has a dependency defined for 'Y'

Question

I\'m getting the following error in NuGet while trying to install package Microsoft.AspNet.Server.IIS

Attempting to resolve dependency \'Microso         


        

Answer 1

I was getting the issue 'Newtonsoft.Json' already has a dependency defined for 'Microsoft.CSharp' on the TeamCity build server. I changed the "Update Mode" of the Nuget Installer build step from solution file to packages.config and NuGet.exe to the latest version (I had 3.5.0) and it worked !!

Answer 2

The only solution that worked for me was to uninstall nuget completely from Visual Studio 2013 and then install it again with the obligatory restart of VS in between.

Answer 3

I tried the update, but it did not work for me. Helped:

1. Uninstall NuGet => Tools => Extensions and update => Installed
2. Install NuGet
3. Reload Visual Studio

Answer 4

In my case I had to delete the file NuGet.exe in the Project folder/.nuget and rebuild the project.

I also have in NuGet.targets the DownloadNuGetExe marked as true:

<DownloadNuGetExe Condition=" '$(DownloadNuGetExe)' == '' ">true</DownloadNuGetExe>

Hope it's helps.

Answer 5

I fixed a similar issue in my solution by:

1. Opening up a command prompt
2. Navigating to the .nuget folder in my solution
3. Running nuget update -self

This upgraded the copy of NuGet.exe that was in my solution from 2.8.0 to 3.4.4, which fixed the 'X' already has a dependency defined for 'Y' error that was stopping it from downloading SSH.NET automatically before building.

(If your solution doesn't have a copy of NuGet.exe in it - and it might not - then you should try the solution in TN's answer instead)

Answer 6

I was getting this issue on our TeamCity build server. I tried updating NuGet on the build server (via TC) but that didn't work. I finally resolved the problem by changing the "Update Mode" of the Nuget Installer build step from solution file to packages.config.