As much your HDD has less space you have. If it is familiar for you, it is time to chech what do you have on your HDD. Using tools such as SpaceSniffer to find which folders are taking up precious space on your drive might show that the Installer folder located in Windows is one of them.
If you check the Installer folder in Windows (C:\Windows\Installer), you will most likely find a lot of MSI and MSP files in there taking up a few gigabytes of your hard drive, with some people even reporting 10GB+.
The Windows Installer UnUsed Files Cleanup Tool (WICleanup) by KZTechs is able to scan for orphaned MSI and MSP files in the \Windows\Installer folder and offers you an option to delete them from the comfort of a graphical user interface. For scripts and command line usage, WICleanup also includes a command line version in the archive (WICleanupC.exe).
ATTENTION: If you do it on machines on which you have SQL Server installed you may have to rebuild the operating system and reinstall SQL Server.
If you already did the cleaning of Installer folder and need restore the files, you can use Windows Installer Cache Diagnostic
Always make sure you have latest good backup of your system.
