Issue:

Installation of SQL Server 2008 might fails with below error on 64-Bit Operating system.

MSI Error: 1719 The Windows Installer Service could not be accessed. This can occur if you are running Windows in safe mode, or if Windows Installer is not correctly installed. Contact your support personnel for  assistance.

Resolution:

Delete HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msiserver\WOW64

Run command: c:\windows\system32>misexec /regserver

Run command c:\widnows\syswow64>msiexec /regserver

Restart Windows Installer Service.

Root Cause:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msiserver\WOW64 with REG_DWORD = 1 is used to make the installer run in 32 bit mode on 64 –Bit systems assuming windows is 32-bit. This is helpful in running installers that are not compatible with 64bit OS

However, most of the 32bit installers are compatible with 64bit OS and do not need this value to 1. When the value of WOW64 is set 0 it returns the actual OS architecture to the installer. If set to 1 then it returns OS architecture as 32-Bit making Windows Installer to run in 32-bit mode.

Written By: -     Anmol Bhasin,SE,Microsoft GTSC
Reviewed By: -  Karkhick Karishnamurthy,TL,Microsoft GTSC
                       Pradipta Das,TL,Microsoft GTSC