NuGet Package restore failed for project myProjectWeb: Unable to find version '3.0.1' of package 'AppForSharePoint16WebToolkit'

Question

It's a provider hosted project. It used to work until very recently.

If I create a completely new project/solution, then it works.

If I start the old one, or redownload it from source control, I get the following error:

NuGet Package restore failed for project LocalTheaterWeb: Unable to find version '3.0.1' of package 'AppForSharePoint16WebToolkit'

I tried Update-Package -Reinstall but the problem stays.

Any ideas?

Answer 1

The solution of Scott Hillier did it for me:

http://www.shillier.com/archive/2014/08/05/nuget-package-restore-fails-for-sharepoint-2013-provider-hosted-apps.aspx

I often take advantage of the NuGet Package Restore capability to reduce the size of my projects when saving or sharing them. Today, I discovered an issue with this process when building SharePoint 2013 Provider-Hosted Apps against SharePoint Online. Here are the steps to reproduce and the fix:

1. Create a Provider-Hosted App in Visual Studio 2013 using a SharePoint Online site for debugging.
2. Right click solution and "Enable NuGet Package Restore"
3. Save and Close Project
4. Delete the “packages” folder from project directory
5. Open Project in Visual Studio 2013
6. Rebuild, receive error “Unable to find AppForSharePoint16WebToolkit”
7. Open Packages.config file
8. Change “AppForSharePoint16WebToolkit” to “AppForSharePointWebToolkit”
9. Rebuild – successfully this time. Apparently, the "AppForSharePoint16WebToolkit" package is not available through the NuGet Package Manager, but the older "AppForSharePointWebToolkit" package is available.

Answer 2

The error message suggests that NuGet cannot find the AppForSharePoint16WebToolkit package in your package sources. So check the following:

1. The correct package source is selected whilst doing the Update-Package -Reinstall.
2. Check the package source that hosts the NuGet package is enabled. If you are using a recent version of NuGet the package restore should use all the enabled package sources.
3. See if the solution or project has its own NuGet.config which is overriding the package sources.

Without further information my guess is 3. since you say it works for a new project.

You can also run Fiddler to see what package sources NuGet is using as it tries to restore.