Windows Installer Folder Management (can get huge)

[mettelus]

The Windows/Installer folder is a protected folder, so will not typically be on people's radar. I do images monthly, so as that image file began to grow, I took a closer look at the C drive. I use junctions quite a lot (not a solution for this particular folder), so after the Windows/Installer folder crept up above 20GB, I began researching in more detail. Because of the particular status of this folder, I wanted to give folks some insight on what I have found to be the most elegant solution (leaving it in place, but identifying what is in it and why). There is some info for this folder online, but solutions such as moving the contents is not elegant since you need to move them back for certain installs/uninstalls and you cannot readily identify what programs the files are for. Creating a junction actually breaks the ability for some (msi) installers to work, so that is messy as well. The simplest path for me was the following:

First, how big is it? Although you can show/hide protected folders in Windows Explorer, this becomes a pain doing it each time. I use TreeSize Free (run as administrator), and in that application Home->Select Directory->C Drive. The tree defaults to biggest to smallest, and expanding the "Windows" element will probably have the Installer folder listed at the top. I saw a post of a person complaining theirs had gotten to 90GB, but 20GB was enough for me. When all was said and done, mine is still at 12.5GB, with DaVinci Resolve being the biggest offender (at 1.42GB).

Second, what is in it, and why? There is a utility specifically focused on the Windows/Installer folder called PatchCleaner. This has two useful functions. First is the obvious one that it will find orphaned installers and allow you to move them to another location (another drive is preferred). Although this gets some, it barely put a dent in what was in there (a mere 200MB for me). However, when you run that program, in the upper right there is a "details..." link next to the "files still used." That pops up a list of what is in the directory by owner, so clicking the top of the "File Size" column twice, you can get a listing of the files largest to smallest. If you click on a file, the "Product Details" in the lower right will help clarify what it belongs to, and you can decide from there. The eye-opener for me was that numerous upgrades had duplicate listings, some not only for the program (old version left in place), but for their additional content (duplicates, but tied to different versions). From there I went in and uninstalled previous versions of things I never use anymore (Corel was the biggest offender for me, but there were others), but there seemed to be a common pattern of upgraded items having more than one file in the list (whether it be the previous version's installer, or duplicate content files). Not all programs put hefty files in the Installer directory, but those that do are the ones to be aware of. I didn't go beyond files smaller than 300MB in size, but the ones bigger than that got scrutinized.

I hope this can be of help to some folks. I have 530 programs installed but try to keep C drive images to 100GB or less. When images start creeping above that, I go into create junctions, but junctions do not work on this particular folder, and this folder won't be obvious to most unless you actually go looking for it.