The Windows Installer Cache, located in c:\windows\installer folder, is used to store important files for applications installed using the Windows Installer technology and should not be deleted. If the installer cache has been compromised, you may not immediately see problems until you perform an action such as uninstall, repair, or update on a product.
When a product is installed using Windows Installer critical files are stored in the Windows Installer Cache (default is C:\Windows\Installer). These files are required for uninstalling and updating applications. Missing files cannot be copied between machines since they are unique.
How to Determine if you are Missing Files
The Windows Installer Cache Verifier Package troubleshooter is integrated with the Microsoft Support Diagnostics service. This service can perform automated diagnostic analysis to identify solutions.
2. If you are prompted, sign in by using your Windows Live ID.
3. To create a new diagnostic session select Windows Installer Cache Diagnostic from the list.
4. Enter a descriptive name for the Session Name, then click Create.
Note You will use the name that you enter to view the analysis results later.
5. Follow the instructions to download and run the analysis package.
6. To view the analysis results select Recent Sessions which is near the top of the site.
7. Click the Session Name you created to view the results. Alternatively a report is available locally. See More Information section.
If files are missing from the Windows Installer Cache, you will have to rebuild the operating system and reinstall applications.
Microsoft support engineers cannot help you recover missing files from the Windows Installer cache.
Some third-party entities claim to be able to rebuild or repair the Windows Installer cache. For legal and supportability reasons we cannot recommend or endorse any of these entities. If you use such third-party products and recommendations you do so at your own risk.
If you have backups for your system prior to the file deletions here are some options
System RestorePoints available only on Client operating systems.
Restoreable System State Backup.
Disaster recovery methods that can restore the full system state backup
Reinstall the operating system and all applications.
Full system state restores are required. It is not possible for example to replace only the missing files from a previous backups.
Other Error Messages
Other error messages that can results from missing Windows Installer Cache files. Many of these are SQL specific. They are not limited to this issue and can be found in either the Setup or MSI Verbose logs.
1612 The installation source for this product is not available. Verify that the source exists and that you can access it.
1620 This installation package could not be opened. Contact the application vendor to verify that this is a valid Windows Installer package.
1635 Unable to install Windows Installer MSP file
This update package could not be opened. Verify that the update package exists and that you can access it, or contact the application vendor to verify that this is a valid Windows Installer update package.
1636 Unable to install Windows Installer MSP file
1642 The upgrade cannot be installed by the Windows Installer service because the program to be upgraded may be missing, or the upgrade may update a different version of the program. Verify that the program to be upgraded exists on your computer and that you have the correct upgrade.
1706. The endpoint format is invalid.
1714 MSP Error: 1714 The older version of Microsoft SQL Server Native Client cannot be removed.
You are strongly encouraged to download this package from the portal rather than reusing a portable copy. If you submit the results the latest diagnostic rules will be used. This package is frequently updated.
The report is available immediately after running this tool without submitting the results to Microsoft. The report is an XML file and will be located in the user temp folder similar to the following.