Is it safe to delete C:\Windows\Installer on Windows 10?

According to Microsoft employee joscon in the Microsoft Technet post "Can you safely delete files in the %windir%\Installer directory?", it is not safe to delete C:\windows\install or any files within it, and the post explains why as well.

I've referenced and quoted the portions of the post that relate to your question and helped make it more clear and concise for the specific subject matter of your inquiry.

Can you safely delete files in the %windir%\Installer directory?

The answer is flatly: "No".

Let's talk about why this is a bad idea:

1. First, it is not supported. If you remove files from this directory and have issues, you may need to reinstall the application to get back to a good state.

2. This particular directory's job is to act as a cache location for Windows installer based applications. It holds stripped down versions of the Windows installer data files. During application install, update of the application or application removal, this directory is used by the application to confirm the existence of previously installed items to determine the next steps the installer needs to take.

   • The files are different from machine to machine, so if you expect to delete the files in the directory and then copy them over from another machine, that would be incorrect. Removing items from here could cause you to have application crashes, or worse, require the re-installation and patching of the application.

The overall idea that you really should not remove items in the Windows directory. We build and test our software based on the existence of specific files and directories. When those files and directories don't exist, bad things can and will happen. However, that is a generalization that usually upsets many people so let's be more specific.

The proper way to alleviate space pressure in this directory is to uninstall any unneeded applications.

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The C:\Windows\Installer folder is where some but not all applications uninstall files and folders are stored.

If you want to remove applications, use the Control Panel Programs and Features to uninstall them. It is also possible to run Disk Cleanup (cleanmgr.exe) in elevated mode to help free up space.