In my opinion, one of the worst things ever to come out of Microsoft is the Windows Installer Cache. Actually, I shouldn’t be that harsh. There is a worse thing that is behind the problems with the Installer Cache.
The cache is a hidden folder located at %WINDIR%\Installer. If you have been running Windows for any respectable length of time and installed a few programs to use; you will see that this folder is filled with MSP and MSI files. It is quite possible that many gigabytes of space are taken up with these files.
The curse of this design is that many users will delete these files to gain back that space. The consequences of which are that many programs (notably, SQL Server) will break during future upgrades or installs. Sometimes this problem is so severe that the best answer for resolution is formatting and reinstalling everything.
That is where I find myself this morning. I bought a 32 GB solid-state drive to install Windows on. But I forgot about the piggish Installer Cache and the drive quickly filled up completely. I moved some of those offending files (rather than delete them) to larger spinning-rust drives. This is merely a Band-Aid temporary solution though.
Today, I will add a new 120 GB SSD drive to my box and rebuild.
I hate rebuilding. There is always something that I forget to backup.
The "worse thing" that I initially mentioned is that Windows Setup should come with advanced options that give one finer-grained control about file location. These options may not be for everyone; but they should exist!
Please Microsoft, I’m begging you! Let me choose the location for the Windows Installer Cache during setup!