Uninstall an Existing Instance of SQL Server (Setup)

This article describes how to manually uninstall a stand-alone instance of SQL Server. By following the steps in this topic, you also prepare the system so that you can reinstall SQL Server.

Important
To uninstall an instance of SQL Server, you must be a local administrator with permission to log on as a service.

Note
To uninstall a SQL Server failover cluster, use the Remove Node functionality provided by SQL Server Setup to remove each node individually. For more information, see Add or Remove Nodes in a SQL Server Failover Cluster (Setup)

Consider the following important information before you use this procedure to uninstall SQL Server:

• We recommend that you use Uninstall a program in Control Panel to uninstall SQL Server.

• Before you remove SQL Server components from a computer that has the minimum required amount of physical memory, make sure that the page file size is sufficient. The page file size must be equal to two times the amount of physical memory. Insufficient virtual memory can cause an incomplete removal of SQL Server.

• If you have multiple instances of SQL Server 2012, the SQL Server Browser uninstalls automatically when the last instance of SQL Server 2012 is uninstalled.

  However, if an instance of SQL Server 2005 exists after you uninstall the last instance of SQL Server 2012 SQL Server Browser remains installed to assist connections to the instance of SQL Server 2005. You can leave the SQL Server Browser installed with SQL Server 2005 and it will continue to function correctly.

  If you want to uninstall all components of SQL Server 2012, you must uninstall the SQL Server Browser component manually from Programs and Features in Control Panel. If you remove the SQL Server 2012 Browser when a SQL Server 2005 instance is present, connectivity to SQL Server 2005 might be disrupted. In this situation, you can reinstall SQL Server Browser in one of the following ways:

  • Repair the instance of SQL Server 2005 by using Programs in Control Panel.

  • Install an instance of the SQL Server 2005 Database Engine or Analysis Services.

• SQL Server Compact runtime and query tools are installed when you install SQL Server Management Studio and SQL Server Integration Services. SQL Server Compact Server tools are installed if you create a replication subscription involving SQL Server Compact. They are not automatically uninstalled when SQL Server and tools are uninstalled. You will need to uninstall the SQL Server Compact components manually from Programs in Control Panel.

Before you remove SQL Server, follow these steps:

• Back up your data. Although this is not a required step, you might have databases that you want to save in their present state. You might also want to save changes that were made to the system databases. If either situation is true, make sure that back up the data before you uninstall SQL Server. Alternatively, save a copy of all the data and log files in a folder other than the MSSQL folder. The MSSQL folder is deleted during uninstallation.

  The files that you must save include the following database files:

  • Master.mdf

  • Mastlog.ldf

  • Model.mdf

  • Modellog.ldf

  • Msdbdata.mdf

  • Msdblog.ldf

  • Mssqlsystemresource.mdf

  • Mssqlsustemresource.ldf

  • Tempdb.mdf

  • Templog.ldf

  • ReportServer[$InstanceName] (This is the Reporting Services default database.)

  • ReportServer[$InstanceName]TempDB (This is the Reporting Services default temporary database.)

• Delete the local security groups . Before you uninstall SQL Server, delete the local security groups for SQL Server components.

• Stop all SQL Server services. We recommend that you stop all SQL Server services before you uninstall SQL Server components. Active connections can prevent successful uninstallation.

• Use an account that has the appropriate permissions. Log on to the server by using the SQL Server service account or by using an account that has equivalent permissions. For example, you can log on to the server by using an account that is a member of the local Administrators group.