Solved What happens to WinSXS?

My Win10/64 Home WinSXS directory is a little over 5GB on disk (about 8.4GB logical space.) When I upgrade to Win11 what happens to WinSXS? Does it get smaller, stay the same size, or get bigger?

Birk said:

My Win10/64 Home WinSXS directory is a little over 5GB on disk (about 8.4GB logical space.) When I upgrade to Win11 what happens to WinSXS? Does it get smaller, stay the same size, or get bigger?

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You can clean the WinSxS folder...

Clean Up Component Store (WinSxS folder) in Windows 10


Works on Win 10 and Win 11.

I guess that depends how you optimize? Mine has 3,29GB on disk (5,75GB size). Windows compressed.

Birk said:

My Win10/64 Home WinSXS directory is a little over 5GB on disk (about 8.4GB logical space.) When I upgrade to Win11 what happens to WinSXS? Does it get smaller, stay the same size, or get bigger?

Click to expand...

Welcome to Eleven Forum

The exact size of WinSxS depends on how many updates you have had since Windows was last upgraded and whether or not you have cleaned up the component store recently. File Explorer does not show an accurate size due to the hardlinks that may be used in the component store. You can find out the actual size of the component store by running the command Dism /online /cleanup-image /analyzecomponentstore in a Command Prompt (Admin).


When you upgrade to W11 the old W10 component store will be completely replaced with a new one for W11. Typically the size will be about the same as the W10 one or a little smaller. My WinSxS for W11 Home is 6.74GB while the install of W10 Home 21H1 that I copied from another machine to upgrade it to W11 now has a WinSxS of 7.39GB on that original machine.

Windows 11


Windows 10

I just cleanly installed Windows 11 build 22454 on Friday night, and I've got about 95% of my stuff back installed (haven't installed the games yet) and this is mine:

I've done the WinSXS cleaning many times. It is good news that Win11 starts over with a clean directory.

WinSXS is a special folder, basically it tells Fibs!!

in order to ensure that applications that require older versions of .DLL and some other support library files when a .DLL file is updated the system creates a symbolic link to the older version and this is stored in WinSXS. this phantom copy is used to redirect to the actual older copy, if any program executable calls the older .DLL (in reality it adds a link to all versions of the .DLLs and cleans up those that are deleted when systems are updated)

Now, a Symbolic link is designed to look identical to the OS as the original files or folder that it points to this includes it's size and Size on Disk so that executables can confirm it's the right file, however, the actual Symbolic link only takes up a few bytes.

before worrying too much about a huge WinSXS folder if possible check the size of the folder from outside Windows ( live linux or similar ) you may be surprised by the actual size reported

This is the way it was explained to me back in my server days , current MS info ...

barman58: you are exactly correct. WinSXS (Windows Side by Side) was created back in the old days of "DLL Hell" which happened when different developers/vendors used the same DLL file in their software distributions. All sorts of problems developed when Windows would release an update that had updated DLL's of the same name as those already in use, but with slightly different functionality.

The initial approach to fix this was to just let each piece of software store it's own copy of it's DLL's, but this of course resulted in many duplicate copies. I'm guessing that's when someone at Microsoft developed the concept of Symbolic Links, sometimes called Junction Links, which appear to Windows as real DLL's but are actually just a pointer to the physical DLL in some other place.

The nice thing about this concept is that these symbolic links work for directories just as well as individual files. There is an old program called Junction Link Magic (Download Junction Link Magic 2.0.3.0)
that lets people create links of their own. I use this to get directories normally on my boot drive moved off to a different drive so my Macrium backups don't take so long to complete. I've not yet been brave enough to try this for WinSXS though.

Mine's a bit bigger, but tolerable at under 7 GB:

HTH,
--Ed--

@Birk

I would not advise using junctions/Symbolic links within WinSxS as the Russian doll effect on the sub directories could cause unpredictable results - of course It may work perfectly but I personally would just not trust it

barman58 said:

@Birk

I would not advise using junctions/Symbolic links within WinSxS...

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@Birk
Microsoft don't use junctions/symbolic links in WinSxS. They use hardlinks.

For operating system files, it can appear that more than one copy of the same version of a file is stored in more than one place on the operating system, but there’s usually only one real copy of the file. The rest of the copies are just “projected” by hard linking from the component store..... This might lead you to think that the WinSxS folder takes up more disk space than it really does....

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There are three types of file links supported in the NTFS file system: hard links, junctions, and symbolic links.....

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