title: Unable to Install Any Package in Visual Studio 2015
body: <p>I've tried every package I could possibly find and none of them will install in my project.  I've installed every update listed in the Extensions and Updates list that were available.  When I attempt to install SendGrid for example, this is the result (as is the result with all other packages):  </p>
  
  <pre><code>Attempting to gather dependencies information for package 'Sendgrid.6.1.0' with respect to project 'UI\MyApplication.MVC', targeting '.NETFramework,Version=v4.5.2'
  Attempting to resolve dependencies for package 'Sendgrid.6.1.0' with DependencyBehavior 'Lowest'
  Resolving actions to install package 'Sendgrid.6.1.0'
  Resolved actions to install package 'Sendgrid.6.1.0'
  For adding package 'SendGrid.SmtpApi.1.3.1' to project 'MyApplication.MVC' that targets 'net452'.
  For adding package 'SendGrid.SmtpApi.1.3.1' to project 'MyApplication.MVC' that targets 'net452'.
  Adding package 'SendGrid.SmtpApi.1.3.1' to folder 'C:\Users\Keith\Source\Workspaces\MyApplication\MyApplication.MVC\packages'
  Install failed. Rolling back...
  </code></pre>
  
  <p>I can't be the only one on the planet having issue with Visual Studio 2015 and the new and "improved" NuGet Package Manager.  </p>
  
  <p><strong>UPDATE:</strong><br>
  Well, must be something odd in my solution because I created a new project from the VS2015 template (web) and the packages install just fine.  When I find out the issue, I'll post the resolution in the event others run into the same problem.  </p>
  
  <p><strong>UPDATE 2:</strong><br>
  Ok, it's not our solution.  We created a new solution from scratch again (this has wasted a lot of our development time might I add), added a couple of packages (Identity, EF, SendGrid) and after checking the solution in to VSO, another developer performs a fresh creation of the branch and build errors occur.  When I go to the NuGet packages for an individual project, it acts as though none of the packages I have added are available.  Anyone else experiencing this?</p>