Adding reference to Class Library issue in ASP.NET 5 beta 7 - asp.net

Question

I removed dnxcore50 from project.json and added an empty class library to solution. When I add reference to class library, project build correctly but when I want to publish project, I will get this error:
The expected lock file doesn't exist. Please run "dnu restore" to generate a new lock file
dnu restore command also not helps.
If i remove reference to class library, publish works fine.
project.json:
{
"webroot": "wwwroot",
"userSecretsId": "aspnet5-AdsProject-e7d42575-2bc4-4316-881a-236435c407a1",
"version": "1.0.0-*",
"dependencies": {
"EntityFramework.Commands": "7.0.0-beta7",
"EntityFramework.SqlServer": "7.0.0-beta7",
"Microsoft.AspNet.Authentication.Cookies": "1.0.0-beta7",
"Microsoft.AspNet.Authentication.Facebook": "1.0.0-beta7",
"Microsoft.AspNet.Authentication.Google": "1.0.0-beta7",
"Microsoft.AspNet.Authentication.MicrosoftAccount": "1.0.0-beta7",
"Microsoft.AspNet.Authentication.Twitter": "1.0.0-beta7",
"Microsoft.AspNet.Diagnostics": "1.0.0-beta7",
"Microsoft.AspNet.Diagnostics.Entity": "7.0.0-beta7",
"Microsoft.AspNet.Identity.EntityFramework": "3.0.0-beta7",
"Microsoft.AspNet.Mvc": "6.0.0-beta7",
"Microsoft.AspNet.Mvc.TagHelpers": "6.0.0-beta7",
"Microsoft.AspNet.Server.IIS": "1.0.0-beta7",
"Microsoft.AspNet.Server.WebListener": "1.0.0-beta7",
"Microsoft.AspNet.StaticFiles": "1.0.0-beta7",
"Microsoft.AspNet.Tooling.Razor": "1.0.0-beta7",
"Microsoft.Framework.Configuration.Abstractions": "1.0.0-beta7",
"Microsoft.Framework.Configuration.Json": "1.0.0-beta7",
"Microsoft.Framework.Configuration.UserSecrets": "1.0.0-beta7",
"Microsoft.Framework.Logging": "1.0.0-beta7",
"Microsoft.Framework.Logging.Console": "1.0.0-beta7",
"Microsoft.Framework.Logging.Debug" : "1.0.0-beta7",
"Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.0.0-beta7"
},
"commands": {
"web": "Microsoft.AspNet.Hosting --config hosting.ini",
"ef": "EntityFramework.Commands"
},
"frameworks": {
"dnx451": {
"dependencies": {
"ClassLibrary": "1.0.0-*"
}
}
},
"exclude": [
"wwwroot",
"node_modules",
"bower_components"
],
"publishExclude": [
"node_modules",
"bower_components",
"**.xproj",
"**.user",
"**.vspscc"
],
"scripts": {
"prepublish": [ "npm install", "bower install", "gulp clean", "gulp min" ]
}
}

Answer 1

Be sure you resolved all reference warnings and don't mix different beta versions.
Are both versions still in beta7 incl your visual studio??
Try upgrade to beta 8 all projects, dnvm,dnx and visual studio
See the home repro

Answer 2

I know this is a bit late. I had the exact same issue on beta 7 today. And only with custom libs added.
I got it fixed by going into the folder called "wrap" that gets created when you add your library. In there you'll find a project.json. Run a dnu restore on that folder in cmd.
Worked like a charm for me.