Fix - "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."

While trying to change something in my project, i got the following error.

"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 below solution that worked for me..

Solution:
Delete all files inside the following folder

C:\Documents and Settings\ USER_NAME \Local Settings\Application Data\Microsoft\Microsoft SQL Server Data\SQLEXPRESS

[ Note: Remember to replace USERNAME with your username. ]

Re-Run the application, That's it.