title: Errors in Azure DevOps build - are you missing an assembly reference?
body: <p>I am using <strong>VSTS</strong> (<em>Azure DevOps</em>) for the first time and am setting up my first build (I have previously been using TFS). I'm trying to build a .NET application targeting <em>.NET Framework 4.6</em>. </p>
  
  <p>However I'm getting build errors relating to missing namespaces and / or assemblies. </p>
  
  <p><em>Error CS0246: The type or namespace name 'OwinStartupAttribute' could not be found (are you missing a using directive or an assembly reference?)</em></p>
  
  <p><em>Error CS0234: The type or namespace name 'Http' does not exist in the namespace 'System.Web' (are you missing an assembly reference?)</em></p>
  
  <p><em>Error CS0234: The type or namespace name 'Azure' does not exist in the namespace 'Microsoft' (are you missing an assembly reference?)</em></p>
  
  <p>The issues all seem to be related i.e. the nuget packages aren't getting restored during the build process. </p>
  
  <p>I've therefore added a <strong>Nuget restore</strong> task to the pipeline before my build step.</p>
  
  <p><a href="https://i.stack.imgur.com/SAN7n.png" rel="noreferrer"><img src="https://i.stack.imgur.com/SAN7n.png" alt="enter image description here"></a></p>
  
  <p>And have checked the option <strong>Restore Nuget packages</strong> on the build step. </p>
  
  <p><a href="https://i.stack.imgur.com/6G9IM.png" rel="noreferrer"><img src="https://i.stack.imgur.com/6G9IM.png" alt="enter image description here"></a></p>