Why does the /winsxs folder grow so large, and can it be made smaller?

"Looks like there is finally a way to do this in Windows 8.1 service pack 1 and Windows Server 2012 R2.

Component store analysis tool:

Dism.exe /Online /Cleanup-image /AnalyzeComponentStore

At the end of the scan, the user gets a report of the results (actual size of the winsxs folder) like this:

Component store cleanup:

Today, Component Store Cleanup must be triggered manually by an end-user, either by running DISM, or by using the Disk Cleanup Wizard. In order to make Component Store Cleanup more useful for the average end-user, it will be added into a maintenance task, automatically saving disk space for end-users. To enable this, a change will be made to allow uninstallation of superseded inbox drivers without requiring a reboot (today, all driver installs/uninstalls done by CBS require a reboot).

Dism.exe /online /Cleanup-Image /StartComponentCleanup
Disk Cleanup tool, Clean up system files button.

schtasks.exe /Run /TN ""\Microsoft\Windows\Servicing\StartComponentCleanup"""

"These duplicates and backups are extremely annoying when having limited disk space.

Being in that place, the only way I found that would not jeopardize the OS stability was to generously use the ""Compress contents to save disk space"" setting.

By compressing all those backup directories under the Windows directory, I was able to reduce the directory size from 6.5 GB to 5 GB, with no recognizeable side effects. Using it on some of your stuff outside the Window directory would stretch your 10 GB even more."

You could use VSP1CLN.EXE to make SP1 permanent, which according to this page will free up superseded-by-SP1 components.

"Good news! There is now an officially sanctioned method, from Microsoft, for Windows 7 SP1, to clean out your WinSXS folder.

Install HotFix 2852386 - you can either download manually, or wait for it to come through your Windows Update
This adds a new option to the Disk Cleanup Wizard (Under Clean Up System Files) that you can enable for ""Windows Update Cleanup"". Tick this option.
Click OK

Caveat: You may be unable to un-install certain Windows Updates after running the cleanup of your WinSxS folder."

"Looks like there is finally a way to do this in Windows 8.1 service pack 1 and Windows Server 2012 R2.

Component store analysis tool:

Dism.exe /Online /Cleanup-image /AnalyzeComponentStore

At the end of the scan, the user gets a report of the results (actual size of the winsxs folder) like this:

Component store cleanup:

Today, Component Store Cleanup must be triggered manually by an end-user, either by running DISM, or by using the Disk Cleanup Wizard. In order to make Component Store Cleanup more useful for the average end-user, it will be added into a maintenance task, automatically saving disk space for end-users. To enable this, a change will be made to allow uninstallation of superseded inbox drivers without requiring a reboot (today, all driver installs/uninstalls done by CBS require a reboot).

Dism.exe /online /Cleanup-Image /StartComponentCleanup
Disk Cleanup tool, Clean up system files button.

schtasks.exe /Run /TN ""\Microsoft\Windows\Servicing\StartComponentCleanup"""