How to manage C:/windows/ filling up?

From your screenshot, almost all of the 48 GB inside C:\Windows is coming from two places: C:\Windows\Installer at ~33 GB and the rest largely from WinSxS and component store content. You should not manually delete anything inside C:\Windows or C:\Windows\Installer.

For C:\Windows\WinSxS and general Windows component bloat, first check what is actually reclaimable:

DISM /Online /Cleanup-Image /AnalyzeComponentStore

If it reports reclaimable packages, run:

DISM /Online /Cleanup-Image /StartComponentCleanup

If space is critical and you do not need to uninstall existing updates:

DISM /Online /Cleanup-Image /StartComponentCleanup /ResetBase

That reduces WinSxS by removing superseded component versions. It is the only supported way to shrink that part of C:\Windows.

For Windows Update cache (also inside C:\Windows):

net stop wuauserv
net stop bits
del /s /q C:\Windows\SoftwareDistribution\Download\*
net start wuauserv
net start bits

That clears downloaded update packages, which can consume several GB.

For C:\Windows\Installer at 33 GB, do not delete .msi or .msp files manually. The only supported reduction method is uninstalling software that installed those patches. The Installer folder is a cache required for repair, patching, and uninstall operations. Manually removing files there will eventually break Office, Visual Studio, or other products.

To identify what is generating the Installer growth, uninstall unused large Microsoft products first, then reboot and recheck size. There is no supported DISM or cleanup command that directly purges that folder.

If you want to confirm actual component store size versus hard-linked size:

DISM /Online /Cleanup-Image /AnalyzeComponentStore

WinDirStat often overreports WinSxS because of hard links. DISM shows the true reclaimable amount.

Realistically, on a 120 GB system drive, 40–50 GB for C:\Windows on modern Windows 10/11 is normal. The only safe reductions inside C:\Windows are via DISM component cleanup and clearing SoftwareDistribution. The Installer folder cannot be safely trimmed except by removing the software that created those cached installers.

If the above response helps answer your question, remember to "Accept Answer" so that others in the community facing similar issues can easily find the solution. Your contribution is highly appreciated.

hth

Marcin