trying to update Xamarin.Forms to 2.3 but getting Access to the path 'Xamarin.Forms.Build.Tasks.dll' is denied
<p>In Visual Studio 2015 I'm trying to run the NuGet update for Xamarin.Forms but it fails at </p>

<p><code>Access to the path 'Xamarin.Forms.Build.Tasks.dll' is denied.</code></p>

<p>I tried </p>

<ul>
<li>running as Admin </li>
<li>Made sure file isn't "read only" </li>
<li>Delete the file</li>
<li>manually Clean/Rebuild</li>
</ul>