Windows Installer Cache is a folder created in local computer to store important files for applications installed using the MSI Windows Installer technology. The folder is by default located at C:\Windows\Installer and is hidden (Super Hidden) to protect it against tampering or deletion. Microsoft strictly advises not to delete the content of the folder manually.

The folder contains numerous files and logs, so it can take a significant amount of your hard drive storage. Specially when you install large software packages, the cache size increases by the same ratio.

Purpose of Cache

When a software application is installed using Windows Installer, a stripped version of the original installer file is stored in that particular folder. This is because, any future update to the product requires information about the last update of the product. Without this information, the new patch cannot perform the required installation.

The Safe Method

The Windows Installer Cache can be cleaned safely by using a small Microsoft tool msizap.exe. It is a command line utility that removes either all Windows Installer information for a product or all products installed on a computer. For using this tool, you have to get the Windows SDK Components for Windows Installer Developers. Unfortunately most of us are not familiar with this kit, and that is a big problem.

However, you may choose the unofficial way to solve your needs. But remember again, never move or delete any files from the Windows Installer Cache manually.