Hi @WinTechie ,
The C:\Windows\Installer folder contains Windows installer cache, it's used to store important files for applications installed using the Windows Installer technology and should not be deleted.
The installer cache is used to maintain (remove / update) the applications and patches installed on the computer. The installer files are a record of file versions and registry dependencies involved in a particular application or application update installation. The availability of this record in the cache helps to uninstall and update applications properly.
For more information, you can refer to the blog post over here:
https://learn.microsoft.com/en-us/archive/blogs/joscon/can-you-safely-delete-files-in-the-windirinstaller-directory
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Best regards,
Leon