SQL Server 2005 Service Pack 3 won’t install

Solution 1:

This fixed it for me

http://www.sqlnewsgroups.net/group/microsoft.public.sqlserver.server/topic23830.aspx

Essentially:-

Remove the following registry subkeys that store SID settings:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL.X\Setup\SQLGroup HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL.X\Setup\AGTGroup HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL.X\Setup\FTSGroup HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL.X\Setup\ASGroup

Solution 2:

This seems to be an issue when you have installed a named instance in a location other than the default - possibly in a folder named "MSSQLServer".

You might be able to move the instance to another location and complete the installation.

"MSSQLServer" is the default service name of the Database Services component.