You can safely shrink WinSxS, Windows.old, hiberfil.sys and restore points, but only with the tools Windows provides for each, and every one of them costs you something: a way to roll back an update, a way to return to the previous Windows version, hibernation, or old restore points. Never delete these files or folders by hand in File Explorer. This guide covers Windows 11 and Windows 10 and tells you what each item is, how to reduce it and what you give up.
The one rule
When you see a large system file or folder, ask whether Windows has a supported way to make it smaller and whether you are willing to lose what it provides. Most of these items are not waste. They are the price of features: updates you can uninstall, an upgrade you can undo, a PC that resumes where you left it. Check the free space you need, then decide.
Plan to run these steps with administrator rights. Windows asks for confirmation through User Account Control, and some steps need an elevated Command Prompt. Run only the commands in this guide, exactly as written.
At a glance
| Item | What it is | Supported way to reduce it | What you give up |
|---|---|---|---|
| WinSxS | The component store Windows uses for updates and features | DISM component cleanup, Disk Cleanup | The ability to uninstall older updates (with ResetBase) |
| Windows.old | Your previous Windows version after an upgrade | Settings, Storage, Temporary files | The ability to go back to the previous version |
| hiberfil.sys | A copy of memory written when the PC hibernates | powercfg /hibernate off | Hibernation, and Fast Startup |
| Restore points | Snapshots of system settings and files | System Protection settings | Old rollback points |
| pagefile.sys | Overflow space for memory | Leave it system managed | Stability if memory runs short |
WinSxS: do not delete it, shrink it
The WinSxS folder holds the component store. Microsoft's documentation on cleaning up the WinSxS folder (checked in October 2026) is direct about it: do not delete the WinSxS folder, and deleting files from it or the whole folder may severely damage your system so that your PC might not boot and cannot be updated. It says to reduce the size with tools built into Windows instead.
It also explains why the folder looks so big. Files there can appear to exist in several places, but usually there is one copy and the rest are hard links, and File Explorer does not account for that. To see the true size, open Command Prompt as administrator and run:
Dism.exe /Online /Cleanup-Image /AnalyzeComponentStore
The output includes both the size File Explorer would report and the actual size, according to Microsoft's page on determining the actual size of the WinSxS folder. It also says whether cleanup is recommended. Often the answer is that it is not worth doing.
If cleanup is worthwhile, Microsoft describes several options.
- The StartComponentCleanup scheduled task runs automatically and, when it does, waits at least 30 days after an updated component is installed before removing its previous version.
Dism.exe /online /Cleanup-Image /StartComponentCleanupfrom an elevated Command Prompt gives similar results but removes previous versions immediately, without the 30-day grace period, and without the task's one-hour timeout.- Adding
/ResetBaseto that command removes all superseded versions of every component. Microsoft warns that all existing update packages cannot be uninstalled afterwards, though future ones still can.
For nearly everyone the plain StartComponentCleanup is enough, and /ResetBase is only for a PC you do not expect to roll back. Microsoft also says it strongly recommends not disabling component cleanup. Disk Cleanup can do the same job for updates, as mentioned below.
Windows.old: the way back to your previous version
After you upgrade Windows, the previous version is kept so you can go back. Microsoft's page on deleting your previous version of Windows says ten days after the upgrade it is deleted automatically. If you need the space sooner and are confident your files and settings are fine, you can remove it yourself.
Go to Settings, System, Storage, Temporary files, tick Previous Windows Installation(s) and select Remove files. Microsoft's Storage Sense page gives the same route. The action needs administrator rights.
The cost is permanent. Microsoft says deleting your previous version cannot be undone, and you will not be able to go back to it. Wait until you are sure the new version works for you, your programs and your devices. Do not delete the Windows.old folder in File Explorer. Use the Storage page.
hiberfil.sys: the price of hibernation
Microsoft's article on disabling and re-enabling hibernation explains that hiberfil.sys is a hidden system file at the root of the drive where Windows is installed, reserved by Windows when you install it, with a size about equal to the amount of RAM in the PC. If the file is absent, the computer cannot hibernate.
To remove it, open Command Prompt as administrator and run powercfg.exe /hibernate off. To bring it back, run powercfg.exe /hibernate on. Both commands appear in Microsoft's article and in the powercfg reference.
What you lose is hibernation. You may also lose a faster start: Microsoft's powercfg reference says a reduced hibernation file supports only hiberboot, the mechanism behind Fast Startup. If you want a smaller file and not none at all, powercfg /hibernate /type reduced is documented there. Check the current Microsoft page for the behaviour on your version of Windows before using it. On a desktop that you shut down every night and never hibernate, turning it off is a reasonable decision. On a laptop that you close and expect to resume after days, it is not.
Restore points and System Volume Information
Restore points are snapshots of system files, installed apps, the registry and system settings, which Windows can use to roll back after a bad update or driver. Microsoft's System Protection page says the feature is not enabled by default and that you can configure how much disk space it uses. Type Create a restore point in the Start menu, select your drive and choose Configure to see the current setting.
The restore point data is stored in the protected folder System Volume Information on the drive. Do not take ownership of that folder or delete files in it. If you need the space, lower the maximum usage in the System Protection dialog and let Windows manage the rest. Removing restore points takes away the older rollback options. A restore point is not a backup of your personal files, so keep real backups separately.
pagefile.sys
This file lets Windows move data out of memory when memory runs short. Microsoft's article on page file size says page files are system managed by default. Turning the page file off to save space can cause problems when memory fills up, and a small saving does not justify that risk. Leave it on automatic unless you have a specific reason and understand it.
Disk Cleanup and system files
The classic Disk Cleanup tool is still part of Windows 10 and 11, and Microsoft's cleanmgr documentation lists both. Search for Disk Cleanup in the Start menu, select your system drive and choose Clean up system files to include items such as update leftovers. Microsoft's WinSxS page says the option to clean up updates helps reduce the size of the component store. As with Storage settings, read each item in the list before you tick it.
If Windows says Access denied
That message is protection, not a bug. System folders are owned by system accounts on purpose. Do not take ownership, change permissions or run a script found online to force a deletion. If a supported tool in this guide does not remove it, the item is not meant to be removed.
What not to do
- Do not delete files from
WinSxS,System Volume Information,Windows.oldor the page file in File Explorer. - Do not run
/ResetBaseon a PC where you might still need to uninstall a recent update. - Do not remove
Windows.oldin the first days after an upgrade unless you are sure you will not go back. - Do not turn off hibernation on a laptop you rely on to resume.
- Do not treat a restore point as a backup.
System file cleanup in SafeClean
SafeClean's regular cleanup never includes WinSxS, Windows.old or hiberfil.sys. The optional Advanced system cleanup page hands these jobs to Windows' own tools instead of deleting files itself, and labels every action that cannot be undone.
Get SafeClean on Microsoft Store Features and pricing
Frequently asked questions
Can I delete the WinSxS folder?
No. Microsoft warns that deleting it or files in it may severely damage your system so that it may not boot and cannot be updated. Use DISM or Disk Cleanup to reduce it instead.
Is it safe to delete Windows.old?
Removing it through Settings, Storage, Temporary files is a supported action. It cannot be undone, and you lose the option to return to your previous Windows version. Microsoft says it is deleted automatically ten days after the upgrade.
Does turning off hibernation free a lot of space?
It removes hiberfil.sys, whose size Microsoft says is approximately equal to the RAM installed. You lose hibernation, and possibly Fast Startup.
Why does File Explorer show WinSxS as so large?
File Explorer counts hard-linked files more than once. Run DISM with the AnalyzeComponentStore option to see the actual size.
Can I reduce restore points safely?
You can lower the space they may use in System Protection settings. That removes older rollback options, so do it only if you have another way to recover.