What is WinSxS Folder?

This was the query of one of our readers who wanted to know about this folder in Windows 7 called WinSxS. The folder contains thousands of files and occupies Gigabytes of space.

Info about this folder

The folder called WinSxS stands for Windows Side-by-Side and is used to store versions of Windows components that are built to reduce configuration problems with Dynamic Link Libraries (DLL Hell). Multiple versions of components are stored in this folder.

In short this folder usually does not contain any useful data, contents of which may be deleted to reclaim the occupied huge space.

However cleaning this is not easy if the folder does not get clean up by executing a disk cleanup then you might have to format the system to get the used space.

5 Replies to “What is WinSxS Folder?”

  1. This post doesn’t really help, now does it!?
    I have a problem with the size of winsxs and this is no solution. I think the title is a bit misleading.

  2. this folder winsxs, don’t delete it your windows must crash.

    If you delete components from the WinSxS folder like the manifets or the assemblies, etc, you could be in trouble. Each system would react differently. What may work for one could break another! For instance, if you install a program that requires that particular assembly, which you may have deleted, then that program will just not run! Compressing the folder is also a no-no, as it could cause problems during WindowsUpdates or while installing a Hotfix.
    The safest way to clean it, is by simply uninstalling applications which you don’t require. However, this too is not fool proof, as many applications still leave behind their files here, since they may be shared between other applications. So the probability of dud unused dll’s being left behind is quite high.

    And if you are into trying out new software or installing and uninstalling frequently, you may notice that your winsxs size is indeed large, as Vista will store multiple copies of these dll files, in order to let multiple applications without compatibility problem.

  3. Completely useless post that just states the problem. Very misleading title, there is no solution posted at all.

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