IIS ApplicationPoolIdentity does not have write permission to 'Temporary ASP.NET Files'

 

1. Open a Command window as an administrator (Start / Programs / Accessories, then right-click over Command Prompt, then choose "Run as administrator").

2. Enter the following command:

   C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Aspnet_regiis.exe -ga domain\user
   

Substitute your domain and user for domain\user in the example above. That's all it took.