What is in the c:\Windows\installer

[Travis]

I've just installed a new and quite large hard disk and now that I've
got the space I'm trying to free up lots of room on my C: partition so
I can defrag the hard disk regularly and hopefully speed up my
machine. Defrag requires about 15% spare space in order to work
properly, but I've only succeeded in getting it to about 13% free.

However the defragmentation report, which showed the list of files
which couldn't be defragmented, included a whole bunch of 455 megabyte
files called \windows\installer\*.msp

What are they for? Can they be deleted or, better yet, moved to one
of the bigger partitions I'm using for data or programs which now have
about 80% free space?

 

[Guest]

The installer is also the 'uninstaller'. If you are going to keep track of
everything in and out, just like the 'system restore' files, you do it in a
'stack'. You don't get to 'pull a tray out of the middle'. There are a lot of
system things you can't put on another drive, and running against that
reality has caused a lot of irritation, especially for the owners of smaller
systems.

I have seen the same problem a lot of times, today no different than a
decade ago, it's not possible to 'put 10 pounds of stuff in a five pound bag'
You have so many things installed that the system requires more space than
you started with. That's not to say that a nice small system partition isn't
a desirable thing, it certainly is, especially for defragging, checking the
disk, repairing, and so on. (Not to mention the RAID principal of replacing
failing disks and making 'mirrors'.)

It comes down to: Give up something, or move the system to a bigger partition.

Good Luck.