连接字符串“用户登录失败”

Question

I'm trying to connect to my database using the following connection string:

Data Source=LORDKANELSNEGLE\SQLEXPRESS;AttachDbFilename="C:\Program Files\Microsoft SQL Server\MSSQL13.SQLEXPRESS\MSSQL\DATA\Database.mdf";Integrated Security=True;MultipleActiveResultSets=True

However, this gives me the error Login failed for user "LORDKANELSNEGLE\\Lord Kanelsnegle" , despite me being able to login with those exact credentials in SSMS as shown here.

I've even tried adding the login from the Security tab within SSMS and received this error,

confirming that this login does in fact already exist (as if me logging in with them wasn't evidence enough).

I've read every other post, stackoverflow or other, that I could find regarding failed Windows Authentication logins for SQL Server but none of the solutions worked for me. Ideas?

Answer 1

You should remove AttachDbFilename="C:\\Program Files\\Microsoft SQL Server\\MSSQL13.SQLEXPRESS\\MSSQL\\DATA\\Database.mdf from your connection string.

You don't use localdb but fully functional Express Edition .

I imagine that your database is permanently attached to the instance and there is no need to re-attach it. So I think if you look in your SQL Server error log you'll see the error saying that it was impossible to attach that database because it's already attached and it was the reason of login failure.

Another reason can be that your login is not mapped to that database. In this case unless it's sysadmin it cannot enter the database. And this reason is also reported in error log . Server does not write the reason to the user in login failed error for security reasons but any sysadmin can find it in error log next to 18456 error