A common troubleshooting Windows Installer technique before vista was to reregister the Windows Installer service. The steps went something like this
Unregister Windows Installer, and then reregister Windows Installer. To do this, follow these steps:
1. On the "Start" menu, click "Run:.
2. In the "Open" box, type "msiexec /unreg", and then press ENTER.
3. On the "Start" menu, click "Run".
4. In the "Open" box, type "msiexec /regserver", and then press ENTER.
This no longer works on Vista and above. This is because the Windows OS install technology itself, called CBS aka Component-Based Servicing, has moved all service registration into it's own declarative format. CBS also uses an underlying technology called service hardening to have it's Trusted Installer service own all of the OS resources. Using servicing hardening enabled Windows Vista to evolve Windows File Protection into Windows Resource Protection as it now protects both files and registry keys.
References to this troubleshooting step for earlier versions of Windows include
- Error message when you try to add or remove a program on a computer that is running Windows XP or Windows Server 2003: "The Windows Installer service could not be accessed"
- "The Windows Installer service could not be accessed" error message when you try to install Office
- How to resolve common "Windows Installer" problems
- Basic troubleshooting steps for Windows Installer
- How to manually remove and then reinstall .NET Framework 2.0
- "Windows Installer Service could not be accessed" error message when installing application
- You receive an error message when you try to install a program that uses the Windows Installer in Windows XP
- "Disk Error -- Reserved Error (-1601)" error message when you try to install an Office update
- "The Windows Installer Service Could Not Be Accessed" error message when you install a program in Windows XP
- You may receive Error 1721 when you try to remove programs by using Add or Remove Programs in Windows XP
- When you restart a computer that is running Windows Server 2003 or Windows 2000 Server, the computer stops responding, or the "Applying computer settings" screen appears for longer than you expect
- Windows Installer-related event IDs are logged in the Application log when you start an Office program
- Error message when you try to install the .NET Framework 1.1 Service Pack 1 Update from the Windows Update site on a Windows XP-based computer: "Updates were unable to be successfully installed"
- How to troubleshoot Microsoft .NET Framework 1.1 installation issues on Microsoft Windows Server 2003