Fix the Microsoft SQL Server Error 18456 [Login Failed For User]

Try these easy fixes if Microsoft SQL Server error 18456 pop up

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Updated onNovember 8, 2024

updated onNovember 8, 2024

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Logging into the Microsoft SQL Server requires a certain level of permissions and authorization. Hence, issues with the login process can prompt Microsoft SQL Server Error 18456.

Also, it can cause theOperating System not supported by SQL server errorto appear.

What causes the Microsoft SQL server error 18456?

TheMicrosoft SQL Server, Error: 18456 Login Failed for user can occur for many reasons. It indicates that you have entered invalid credentials, permission problems, or SQL server settings impeding the authentication process.

However, common causes that may prompt the error on your PC are:

Other factors may be responsible for the error. Nevertheless, we’ll discuss solutions for fixing it and getting your SQL server Management Studio working.

How do I fix SQL Server Error 18456?

Go ahead with the following preliminary checks:

Proceed with the steps below if you can’t fix the error.

1. Launch the SQL Server as Administrator

Allowing the SQL Server Management Studio to run as administrator will fix any permissions issues affecting it.

2. Change the SQL Server Authentication mode

Running the SQL server in Authentication mode will fix the login issues causing the error. You can check our guide onother Windows hosting SQL serveryou can use.

3. Launch the SQL Server in a Single User Mode

The above steps will check the SQL server’s parameters and assign the administrative role to help fix the issue.

4. Enable the TCP/IP Protocol in the Server Configuration Manager

The TCP/IP Protocol in the Server Configuration Manager will fix network issues liable to cause the Microsoft SQL Server Error 18456.

Alternatively, our readers can checkhow to repair a corrupt SQL server databasefor more information on fixing SQL errors. Likewise, we have a guide onfixing the cannot generate SSPI context errorin SQL Server.

We also have an article on how toprint error messages in SQL Serverwhich might come in handy when debugging your code.

For more questions or suggestions, kindly drop them in the comments section below.

Fix the Microsoft SQL Server Error 18456 [Login Failed For User]#

What causes the Microsoft SQL server error 18456?#

How do I fix SQL Server Error 18456?#

1. Launch the SQL Server as Administrator#

2. Change the SQL Server Authentication mode#

3. Launch the SQL Server in a Single User Mode#

4. Enable the TCP/IP Protocol in the Server Configuration Manager#