SQL Server Error 18456

A Quick Resolution

Topic Views• SQL Server Error 18456 – An Overview• Event Properties Of Error 18456• Causes of SQL Server Error 18456• How to Resolve Error 18456 ?• Conclusion

SQL Server Error 18456 – An Overview

The SQL Error 18456 “Login Failed” occurs due to various reasons. One of the main reason is, The connection is failed to access to the Server after entering the correct Server name .

The below error message displays when the SQL Error 18456 occurs.

Event Properties Of Error 18456 The Login Failed Error 18456 not provide the much detail about occurrence of this

error. The information is hide to prevent from unauthorized user access.  Although, you can view more information regarding to this error by checking Event Viewer.

Causes of SQL Server Error 18456 Mixed mode is enabled and you may trying to connect with

Windows authentication mode.  The Login or Password is incorrect when you are using SQL

Server Authentication. May the SA password you are using has been expired.

How to Resolve Error 18456 ? For Windows 7, Use “Run as Admin” to open SQL Server and check

if the problem is solved. (Use also for Windows Vista) Check, may the Active Directory Windows account is not

corresponding to SQL login

Use SQL SA password, if you are connecting through SQL Server authentication.

Check for SA Expiration by clicking on: Logins > user > properties

Under the General tab, check, if Enforce password expiration is enabled or disabled

Next, Go to Status tab and Check , if “Login is locked out” option is enabled or disabled.

The SQL error 18456 can also occur, if Windows or Mix Mode Authentication is disabled by itself on the database instance. To check this, Right click on database instance and click on

Properties.

Now, under the Security tab check the Server authentication mode.

You need to Restart the SQL Server Service either if you choose “Windows Authentication mode” or “SQL Server and Windows Authentication” To restart the service right click on database instance and click on

Restart.

Conclusion SQL Server error 18456 may arise from several reasons. Mostly the error

occurs, if user forgets its SA password or if user had tried Windows login name with SQL Authentication. The above mentioned steps help you to fix SQL Error 18456. But, if you still facing this error, the SQL Password Recovery software is more preferable to troubleshoot this “Login Failed” error.

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