Error:

Errors occurred during the installation: Error 1603 installing Microsoft SQL native client. See log file for more detailed information

Error Message:

Causes:

1. SQL Native client provider might be corrupted.
2. This error seems to be linked to missing or incorrect registry entries. Uninstall everything related to SQL that might be on your computer.
3. Due to improper SQL uninstallations, your registry is not clean and might be corrupted.

Workaround 1:

Before installing SQL Server

1. Uninstall “Microsoft SQL Server Native Client” component from control panel.
2. Rename the files sqlncli.dll and sqlnclir.rll if they present in path C:\Windows\System32
3. Later run the SQL Server 2005 setup under an administrator account again.

Workaround 2:

When you are at the point of the failure, do not cancel the installation,

Run this registry SqlNativeClientRegistryConfiguration.reg

Download: SqlNativeClientRegistryConfiguration

Workaround3

Launch Regedit as an administrator. In your Start Search field, type regedit.

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\ UserData\S-1-5-18\Components.

Right-click on  and select “Permissions”

In the “Permissions for Components” screen that comes up, click the Advanced button.

In the “Advanced Security Settings for Components” screen that comes up, click the “Owner” tab.

In the “Owner” tab, check the “Replace owner on subcontainers and objects tickbox, select “Administrators” and click Apply.

Workaround 4:

Remove SQL Server 2005 completely from Control panel

Control Panel | Add or Remove Programs | Microsoft SQL Server 2005

In the first dialog, make sure to select the “RELYONDB: Database Engine” radio button.

If RELYONDB is the only instance, then select all check boxes & Click Next and Finish to proceed with the uninstall.

If there is no other SQL instance, I would go on to clean out all SQL components with the following steps.

Uninstall Microsoft SQL Server Native client

Uninstall Microsoft SQL Server Setup support files

Uninstall Microsoft SQL Server VSS writer