title: IIS Express giving a compilation error, denies access to files
body: <p>I am running Visual Studio 2015 on Windows 7. I have a solution with 2 startup projects, both running on IIS Express, and the .NET version is 4.5.2. </p>
  
  <p>Whenever I start the solution for the first time, everything works as expected. However, when I stop the application, make some changes to the source code, and restart, I get this Compilation Error -532462766 screen on startup :</p>
  
  <p><a href="https://i.stack.imgur.com/V2JQ5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/V2JQ5.png" alt="Compilation Error -532462766"></a></p>
  
  <p>The detailed compiler output is filled with lines like this:</p>
  
  <p><code>/R:"C:\windows\Microsoft.Net\assembly\GAC_MSIL\System.Runtime\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Runtime.dll" /R:"C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Temporary ASP.NET Files\vs\268da2e1\665f7c6d\assembly\dl3\a9f1f009\c9360fff_0864d101\ServiceStack.Common.dll"</code></p>
  
  <p>Going back to Visual Studio, and selecting "Clean Solution" gives me these unable to delete file messages (username and projectname removed).</p>
  
  <p><a href="https://i.stack.imgur.com/qT35v.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/qT35v.png" alt="Unable to delete file"></a></p>
  
  <p>The only way to get things working again, is to right-click IIS Express in the notification area, exit the process, then clean the solution in VS2015, and rebuild. Everything works again then, until the next time I need to change something in the source code (which happens quite a lot, being a software developer and all). </p>
  
  <p>It seems IIS Express or Visual Studio, or my Windows user account is not allowed to delete files in IIS Express. I have tried running VS2015 and IIS Express in administrator mode, but no luck. What else can I try?</p>