The C:\Windows\winsxs folder can pose a problem on machines with small hard drives. The concept behind it is that it stores various versions of program files so that Windows always has the version it needs to run a particular program (to minimize the number of “DLL not found” errors). The folder contains a bunch of links to files throughout your hard disk so that Windows can quickly find the versions of different files it needs to run. The problem is that these links are just simple shortcuts. They are hardlinks, which means that the file appears to duplicated in the source location as well as in the winsxs folder. Additionally, backups are stored within that folder as well. As you install software and Windows updates and etc., the folder continues to grow…and grow…and grow…until it is many gigabytes in size (e.g., often 9 gigs or more). If you have a terabyte drive, no problem. But if you have an older computer with a 40GB drive (as I do) or an small, expensive SSD drive (which I sadly do not), this is a painful waste of space.

You can reduce the size of this folder a little bit by upgrading to Windows 7 SP1 and running the following command from an elevated command prompt (Start\type “cmd”\hold down CTRL and Shift and press Enter):

dism /online /cleanup-image /spsuperseded

The software will go in and remove some of the backups from Windows updates that have been superseded by other updates. Running this can reduce the size by a couple gigs. Doesn’t solve the problem, but at least it helps a little bit.

For me, the winsxs folder size was 6.34 GB before the dism command and 4.14 GB afterward, and it removed about 9,000 files from the directory. The total hard disk space consumed went from 26 GB before to 24.5 GB afterward.