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Is it safe to delete from C:\Windows\Installer?

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The link mentioned above talks about Windows XP. I am talking about Windows 7. The behavior of the folder might have changed between the 2 windows and I would like to get an answer regarding this Windows system and not the Windows XP system.

How can I safely delete OR shrink OR delete from the %SystemDrive%\Windows\Installer folder?

Don't tell me to go to http://support.microsoft.com/kb/290301/en-us since it is no longer valid for the following reason:

While the Windows Installer Cleanup utility resolved some installation problems, it sometimes damaged other components installed on the computer

I don't want to move it to another place but to remove stuff from there.

I will be happy to have a tool that does that but will also be happy to understand the logic of files being there.

Please refer to windows 7(64 bit) in your answer.


  • 1
    It's not a duplicate. OP asks HOW, not CAN. Sep 27, 2016 at 14:50

5 Answers 5


If your system drive is small for some reason (partitioning, SSD, etc.), another option is to move C:\Windows\Installer to another, larger drive and replace the original with a junction to the new location.

Everything should continue to work but your system partition will have more space available.


Yes, it is safe to shrink that folder, I've been doing that for ages without any issues. :-)

As for deleting the folder, it is possible, however this disallows to modify/repair/remove software!

  • How do you shrink? I am shrinking now using the compress option. When I said shrink I ment the same as delete. Feb 6, 2011 at 19:59
  • See thread Is it safe to delete files in C:\Windows\Installer? for more details on this topic.
    – Adrian
    Feb 9, 2011 at 22:22
  • @RandallFlagg: Yeah, by shrink I thought about the compress option. Feb 10, 2011 at 12:24
  • Adrian, the link you gave uses an obsolete solution that is also mentioned in my question. I want an automatic tool that can do this but won't ruin other part of the system. Feb 17, 2011 at 9:30
  • @RandallFlagg: And how would a tool automatize this? It's completely your choice what you shrink or delete. A tool can't determine this for you... Feb 17, 2011 at 14:01

The logic of the files being there are: The package you install can require an installer program itself, nowdays there are many many installer programs, and versions of them. The Installer programs are not as backwards compatable as they should be, even when it is only a version change. In fact you can install one package, and then install another that updates the installer, and the updated installer will no longer remove the first install :-) confused yet?

The Installer Program itself is required to re-run , when you wish to do an uninstall (or repair or re-customise) the installation, This entire program of the installer must exist, plus the package that is to be installed.

Luckily it gets worse, because it was not stupid enough before. There are packages which install installers, which install packages with installers. then the installer will run another installer like say the MSIs own installer. This of course does not include when a Installer is repackaged into an interleaved installer, to install some evil poop like a toobar.

Honestly it gets worse than this too, like installing an entire OS Subsystem because the programming subsystem is nessisary for the method of programming that they used to create the program.

so now you have the Installer, and all the install files, the installation package and all of its files, the System restore which is the instalation removal and all of its files, the driver backup and all of that repeated again, the system backup which is all of the files, plus many programs will also put all of the installation files in thier own folder.

The only thing we dont have is stability :-) we just have layers apon layers of mad attempts at self repairing.

Removing the "installers" (installation program) will mean that the installed program cannot be uninstalled, worse some wont install an upgrade, if the program cant be un-installed (using the original parts). There exists also "Is Installed" triggers in the registry (various types), that has to be switched off to re-install (or lapped install). Plus other registry items which can effect all of the above.

Removing the "installation" (the installation package) will mean the program cannot be uninstalled, even if the installer program exists, because the installation package is required for the instalation. (plus registry items again)

Plus having all that does not guarantee that everything does get uninstalled, or that the program will even be able to repair itself with the installation package.

That is why I feel the need to run ANOTHER uninstaller :-) That tracks everything that changes, and can just toss it all out. Without the tracing the full installation (including first run), removing parts and pieces of it will mean it will not be easily removed. Without full tracing of an installation, removal of any of the multitude of parts and pieces, and layers of protection, and repetition, can not be done easily. Because full removal does not actually occur, this usually Leaves the user re-installing the whole friggen operating system from scratch to clean it up.

Sometimes you can Reinstall the original whole installation, (lapped install) to replace all the items you removed (+ all of the above mess), then the installation and un-installation itself will again operate. But Often this also requires resetting any items that can cause the installation to fail (usually in the registry).

the way to Safely remove the leftover junk, is to have a full image backup, and no intention of removing or repairing or updating those programs, other than the full image backup (retract).


To have fully traced the install, and used a full image backup. That way your traced install can be used to remove it, without all that stuff. (which is not without ramifications) Your FULL image backup can always retract your system back to where it was (before or after as needed).
I find that this method is way more effective than layer apon layer of moss growing on what will never be a rolling stone :-) but there is some requirement to know what your doing.

This post fully Illustrates why the Best method is not discussed or adopted to, there are just some thing, you should never have to see. :-)

  • All installers I have seen (except maybe Python) deal with upgrades very cleanly. Also, Windows\Installer is only used by MSI (Windows Installer); all other tools just put the change log and an 'uninstaller' executable in the program's directory. Sep 29, 2011 at 12:09
  • right, MSIs in windows installer, but not all MSIs are windows products. If ALL installers deal with upgrades cleanly,how is it that i have read thousands of threads with Ketch 22 installation, And i do not suppose that the users were to blame when at times there can be threads thousands of users long about it. Do you get isolated working around Super Users :-) who know what they are doing? If ALL other installer . . . then you have not yet seen and traced some of the things I have, Like a Pro video editing package, Office :-) an ATI driver, or a full Creative card package.
    – Psycogeek
    Sep 29, 2011 at 13:52

As stated earlier by PhsycoGeek, you need the installer files. There is a free program from iObit, that is an "UnInstaller." It works great, it cleans up most of registry trash left behind by an uninstall and allows you to remove a damaged installer file or damaged installation with no apparent danger to other files in the subdirectory.

Download "Uninstaller 2.0" from iObit and while you are there download and try "Advanced Systemcare 5.0." Both are free and the Advanced SystemCare is only $12.97, but it works great I have purchased several other cleanup utilities and tried many other and I feel this is the best one. Uninstaller will cleanup your subdirectory and installation problems intelligently.

Hope it helps, Jim


In Windows 7 you can make the SP upgrade permanent what will make the folder smaller(Doesn't answer my question exactly but it reduces the size) by using the follwing command:

dism.exe /Online /Cleanup-Image /spsuperseded

In windows vista this can be achived by using:

  • "The operation completed successfully but the folder remained the same size... unless there were no upgrades to make permanent.
    – Paul C
    Oct 7, 2013 at 23:00

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