I have Windows 7 Pro(x64), SQL Server 2008 developer edition, IIS 7.5 Trying to create a login for IIS APPPOOL\\ASP.NET v4.0 from SSMS->Security->Logins I am not getting the \"L
To fix this issue, try changing the (Process Model) Identity of your website's Application Pool to use the NetworkService account (or the less secure LocalSystem account). By default, IIS7 seems to set the Application Pools Identity to 'ApplicationPoolIdentity', instead of NetworkService or LocalSystem.
You can change the ApplicationPoolIdentity from IIS7 -> Application Pools -> Advanced Settings
Under ApplicationPoolIdentity you will find local system. This will make your application run under NT AUTHORITY\SYSTEM, which is an existing login for the database by default.