Sửa Lỗi Failed to generate a user instance of SQL Server due to a failure in starting the process for the user instance Trong Microsoft Visual Studio

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 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.

Hope this helps.