Dealing with “Login failed for user”(Error 18456) in SQL Server

In this article we attempt to diagnose SQL Server Error 18456 and look at its possible causes

The Ms SQL Server application finds a place across an array of organizations in the world today ranging from small businesses to huge corporations. While the software is robust, it is hardly free from errors or knick knacks. It is not uncommon to come across errors messages while working on SQL Server. Amongst those that are more frequently seen is error ID 18456 which often occurs when the user tries to sign in into his/her account. An error message is displayed over the screen stating that the login attempt has been unsuccessful.

Typically the situations unfolds when you are attempting to login, and error message is accompanied by an error state information too.  Let’s look at some of the common causes behind Error 18456

• Error of Validation: It occurs in two situations, the first being if one is signing in from an unfamiliar system, while the second could be due to server being fixed at the windows validation mode. It is easy to overcome this error because there is a possibility of the error to disappear if we switch over this mode
• Inappropriate credentials: At the time of login itself one should assure that all the details are correct. However, this error is said to occur on the time of our first login. It can be resolved by signing in again.
• Inactive User ID: The user in this case must consult the administrator, as there is a possibility that his access to the SQL Server has been denied.

The State information carried by error message can gives us clue about the genesis of the error. The following points explain the possibilities with different error states in detail

1. If the error state is 2 to 5 then it is the case of inactive User ID.
2. If its error state is 6 it means that the login name is inappropriate, these needs to be crosschecked.
3. Error state 7 is related to some flaw in the password.
4. Error state 11 and 12 signify that though the login details are valid but the access to server is denied.
5. Error state 13 implies that SQL server has become inactive.
6. Error state 18 pertains to password authentication issue, which can be easily rectified through its modification. There is also a possibility that the password has been expired.

If the error does not resolve by any of the above suggested remedies then it could be a case of an internal error, which can only be rectified by the administrator.

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Author Introduction:

Alan Chen is President & Chairman of DataNumen, Inc., which is the world leader in data recovery technologies, including access recovery and sql recovery software products. For more information visit https://www.datanumen.com/