Error: Failed to generate a user instance of SQL S

Question

I'm trying to connect to an MDF. I've even gone to the lengths of re-installing sql server express entirely (it is now the only flavor of SQL installed on my box, where previously I had 05 dev and express). I've verified that the paths are all correct, and thus far my google-fu hasn't helped.

The Full exception message is:

Failed to generate a user instance of SQL Server due to a failure in starting the process for the user instance. The connection will be closed.

The Connection string is:

<add name= "CustomerEntities"
     connectionString="metadata=res://*/Data.CustomerModel.csdl|res://*/Data.CustomerModel.ssdl|res://*/Data.CustomerModel.msl;
     provider=System.Data.SqlClient;
     provider connection string='Data Source=.\SQLEXPRESS;
     AttachDbFilename=\App_Data\CustomerDb.mdf;
     Integrated Security=True;
     User Instance=True'"
     providerName="System.Data.EntityClient" />

Additional info:

Several of the references to this error I've found online do not apply to me. For example, one I've seen is where this error occurs when trying to start the user instance over remote desktop (I'm doing this locally). While another suggests that it has to do with leftover files from an old express installation ... I've looked in the prescribed locations and not found those artifacts. I also tried running sp_configure 'user instances enabled', '1', but it said that it was already set to 1.

Answer 1

As noted by others, deleting the contents of directory: c:\Users\\AppData\Local\Microsoft\Microsoft SQL Server Data\SQLEXPRESS solved it for me. A note that may help others, on Windows 7, browsing the c:\users\username dir from document browser does not show the the AppData folder which threw me off for a while (as I thought I did not have the AppData dir) until I discovered that it does indeed exist (but does not show in the document browser in Windows 7), you just have to type in the full path name to get to it.

Answer 2

In addition to the other solutions here, this one may also be helpful. Ensure the Application Pool is running as network service, and not ApplicationPoolIdentity.

This solution was found here: http://blogs.msdn.com/b/webdevelopertips/archive/2010/05/06/tip-106-did-you-know-how-to-create-the-aspnetdb-mdf-file.aspx

Answer 3

ok, it works now! guess it was a compound problem ... the steps I took to resolve it are as such:

1. Changed the following property in the connection string (note the subtle difference): AttachDbFilename=|DataDirectory|CustomerDb.mdf;
2. Deleted the contents of the following directory: c:\Users\<user name>\AppData\Local\Microsoft\Microsoft SQL Server Data\SQLEXPRESS. I thought I had looked for this before, but I had actually looked in the Microsoft Sql Server folder. Again, a subtle difference.

Once I did these two things, the connection started working :-D

Answer 4

I phase this problem with my mdf file in windows form application and i do just restart my computer and my problem is solve.

Answer 5

Have you tried to connect to the SQL Server instance by using SQL Management Studio?

If this also doesn't allow you to connect then it could be because the SQL service is not starting correctly.

Verify that the service is running by checking the services in the control panel.

Answer 6

To fix this, please Open the SQL Server Management Studio Express. In the query editor type this text:

sp_configure 'user instances enabled', 1;
 RECONFIGURE

Run it. Then restart the SQL Server database.