Question

I’ve been experimenting with ASP.Net MVC, and have come across a problem that is probably not specifically MVC related. But I cannot get the authentication in the default MVC application (the one created by the wizard when you create a new MVC project) to work properly under IIS 7 on Windows 7.

If I run under the Visual Studio environment, it works, but if I switch the settings to run under IIS instead, I get the following exception trying to submit the login or registration:

Failed to generate a user instance of
SQL Server due to failure in
retrieving the user’s local
application data path. Please make
sure the user has a local user profile
on the computer. The connection will
be closed.

I believe that this is because the website runs under my own account in Visual Studio, but under the IUSR account in IIS. Google searches on the exception message have been unhelpful so far.

So, can one create a local user profile for the IUSR account? If so, how? Is there something else I should be doing to get the SQLExpress engine to work under the anonymous account in IIS 7?

I also tried configuring the IIS website to use my account, but since this is my home machine, my account doesn’t have a password, and it appears that IIS won’t let a website be configured to use an account without a password. Or, since this is my first experience with IIS 7, and configuration feels very different than IIS 5/6, I am just missing the right setting that will let me configure the account to use for anonymous access.

EDIT: Some additional information. If I empty the App_Data folder and try again from IIS, SQLExpress attempts to create my database and fails, but the exception message has further information with the following suggestions.

SQLExpress database file auto-creation
error:

The connection string specifies a
local Sql Server Express instance
using a database location within the
applications App_Data directory. The
provider attempted to automatically
create the application services
database because the provider
determined that the database does not
exist. The following configuration
requirements are necessary to
successfully check for existence of
the application services database and
automatically create the application
services database:

1. If the applications App_Data directory does not already exist, the
   web server account must have read and
   write access to the applications
   directory. This is necessary because
   the web server account will
   automatically create the App_Data
   directory if it does not already
   exist.
2. If the applications App_Data directory already exists, the web
   server account only requires read and
   write access to the applications
   App_Data directory. This is necessary
   because the web server account will
   attempt to verify that the Sql Server
   Express database already exists within
   the applications App_Data directory.
   Revoking read access on the App_Data
   directory from the web server account
   will prevent the provider from
   correctly determining if the Sql
   Server Express database already
   exists. This will cause an error when
   the provider attempts to create a
   duplicate of an already existing
   database. Write access is required
   because the web server accounts
   credentials are used when creating the
   new database.
3. Sql Server Express must be installed on the machine.
4. The process identity for the web server account must have a local user
   profile. See the readme document for
   details on how to create a local user
   profile for both machine and domain
   accounts.

I’ve pretty extensively confirmed that the first three suggestions have been satisfied. The fourth seems to be the cause of my problems, but I can’t figure out how to do that. And although the suggestion claims there is a readme document that describes it, I have not been able to find that document.

Answer 1

I got this problem as well running under medium trust. The process that creates the database requires at least High trust. You can check this by looking in your Web.Config for

<trust level="TrustLevel" />

If there is no trust specified in your Web.Config, try adding it and set it to either Full or High. If this doesn’t work, there is a machine.config in your IIS which you would need to modify.

That being said, the best route I have found to solve this is to just use aspnet_regsql.exe to create the necessary tables and then change the connection string in your Web.Config to look at it directly.