Failed to generate user instance in SQL Server 2012

Question

I am using .mdf file for connectivity, when I select it it generates error:

Failed to generate user instance in SQL Server due to failure in starting the process for the user instance

I have attached image to make it clear to you.

http://i.stack.imgur.com/B1ae2.png

Can anyone answer my question.

Thank you!!

Answer 1

Try following steps :

1. Stop all user instance processes of SQL Server running under your local account (open up task manager and look for sqlsrv.exe process and end it)

2. Delete all files in the %LOCALAPPDATA%\\Microsoft\\Microsoft SQL Server Data\\SQLEXPRESS folder

3. F5 again

The problem is known issue. SQL Server Express cannot create a user instance using the set of engine files in your local app data folder, deleting them should allow SQL Server to recreate them with the correct credentials for you to F5 successfully.