title: Could not load file or assembly Microsoft.Extensions.DependencyInjection.Abstractions in Sitecore 8.1 Project
body: <p>Could not load file or assembly 'Microsoft.Extensions.DependencyInjection.Abstractions, Version=1.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60' or one of its dependencies. The system cannot find the file specified.</p>
  
  <p>I tried clean and rebuild the solution and deleted bin and obj still I got same error. I'm using sitecore 8.1.</p>
  
  <p>Stacktrace:</p>
  
  <pre><code>    [FileNotFoundException: Could not load file or assembly 'Microsoft.Extensions.DependencyInjection.Abstractions, Version=1.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60' or one of its dependencies. The system cannot find the file specified.]
      Sitecore.DependencyInjection.&lt;&gt;c__14`1.&lt;GetRequiredResetableService&gt;b__14_0() +0
      Sitecore.DependencyInjection.LazyResetable`1.get_Value() +148
      Sitecore.Configuration.Factory.GetConfigNode(String xpath) +72
      Sitecore.Resources.Media.UploadWatcher.InitializeIgnoreList() +156
      Sitecore.Resources.Media.UploadWatcher..cctor() +85
  
      [TypeInitializationException: The type initializer for 'Sitecore.Resources.Media.UploadWatcher' threw an exception.]
      Sitecore.Resources.Media.UploadWatcher..ctor() +0
  </code></pre>