Deleting C:\Windows\Installer\ files safely on Windows 7 after running WinDirStat hard drive space usage report

Has anyone successfully deleted the Windows Installer files successfully before? They are taking up 35.1% of my total hard drive space. Which ones are needed and which ones can be purged? In order to see this folder, I had to unhide system files by going to Windows Explorer > Organize (dropdown) > Folder and Search Options > view tab > uncheck ==> Hide protected operating system files (Recommended).

I used WinDirStat program to get these percentages. To see the image in full size, open it in a new tab.

I was told by someone that you should not delete these files, but then I found a utility--Windows Installer CleanUp Utility (very old version) that deleted these. But it doesn't run on Windows 7. If anyone has a later version that they found works, please let me know the path.

Solution 1:

I once deleted the contents of that folder to save disk space. It's not an issue as long as you don't plan to ever uninstall any application from your system ever again.

When you uninstall an application through the "Programs and Features" dialog, Windows will look for the proper uninstallation information in those installers. If they are missing, the application uninstall procedure will fail, leaving you unable to properly remove the application.

So I would highly advise against deleting those files.