How to: 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.

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

• We recommend that you use Add or Remove Programs in Control Panel to uninstall SQL Server.

• If you currently have SQL Server 2008 R2 and SQL Server 2008 instances side-by-side, or if SQL Server 2008 R2 was previously installed on this machine, see Considerations for Side-by-Side Instances of SQL Server 2008 R2 and SQL Server 2008.

• On a computer that is running SQL Server together with earlier SQL Server versions, Enterprise Manager and other programs that depend on SQL-DMO might be disabled. This can occur in the following situations:

  • Side-by-side installations of any combination of SQL Server 2008 R2, SQL Server 2008, SQL Server 2000, and SQL Server 7.0, where any one or more of these instances is uninstalled.

  • Side-by-side installations of SQL Server 2000 with SQL Server 2008, or SQL Server 2008 R2 where SQL Server 2000 is installed after SQL Server 2008, or SQL Server 2008 R2.

  This issue is caused by removal of the registration for the SQL Server SQL-DMO COM library. To re-enable Enterprise Manager and other programs that have SQL-DMO dependencies, register SQL-DMO by running regsvr32.exe sqldmo.dll at the command prompt. For more information, see Troubleshooting an Installation of 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.

• In SQL Server 2005, the SQL Server Browser was an integrated installation together with the Database Engine or Analysis Services. In SQL Server 2008 and SQL Server 2008 R2, the SQL Server Browser is a separate installation, performed automatically with the Database Engine or Analysis Services. If you have multiple instances of SQL Server 2008 or SQL Server 2008 R2, the SQL Server Browser uninstalls automatically when the last instance of SQL Server 2008 or SQL Server 2008 R2 is uninstalled.

  However, if an instance of SQL Server 2005 exists after you uninstall the last instance of SQL Server 2008,or SQL Server 2008 R2, 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 2008, you must uninstall the SQL Server Browser component manually from Programs and Features in Control Panel. If you remove the SQL Server 2008 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 and Features 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 Server and tools are uninstalled. You will need to uninstall the SQL Server Compact components manually from Programs and Features 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. These files are installed as part of SQL Server:

  • Distmdl.*

  • Master.*

  • Mastlog.*

  • Model.*

  • Modellog.*

  • Msdbdata.*

  • Msdblog.*

  • Mssqlsystemresource.*

  • Northwind.* (This database is an optional installation.)

  • Pubs.*

  • Pubs_log.*

  • Tempdb.*

  • Templog.*

  • 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.