Storage Sense and Disk Cleanup: what is safe to delete

Verified 2026-10-293 min read

Which cleanup targets are free space and which ones cost you something, how to run WinSxS cleanup, and what actually fills a modern drive.

Tested onPro (26H2) / Server · Build 26300.9457 / 26100.33650 · x64

Build: 26300.9457 / 26100.33650
Edition: Pro (26H2) / Server
Architecture: x64
Support: Documentation (E1)
Evidence: E1Official documentation
Verified: 2026-10-29
Page type: Task

The short answer

Three different cleanup mechanisms, three different risk levels:

Tool	Frees	Risk
Storage Sense	temp files, recycle bin, old Downloads	low, runs automatically
Disk Cleanup (`cleanmgr`)	Windows Update leftovers, old installs, thumbnails	low, but some items are one-way
WinSxS cleanup (`/StartComponentCleanup`)	superseded component versions	medium — no rollback after

The biggest wins are usually not in these tools: it is the 40GB of games, the 20GB of OneDrive cache, or the hibernation file.

Start with the honest picture

Get-Volume | Select-Object DriveLetter,FileSystemLabel,@{n='SizeGB';e={[math]::Round($_.Size/1GB,1)}},@{n='FreeGB';e={[math]::Round($_.SizeRemaining/1GB,1)}}
Get-ChildItem $env:USERPROFILE -Directory -Force -ErrorAction SilentlyContinue |
  ForEach-Object {
    $s = (Get-ChildItem $_.FullName -Recurse -Force -File -ErrorAction SilentlyContinue | Measure-Object Length -Sum).Sum
    [pscustomobject]@{ Folder = $_.Name; GB = [math]::Round($s/1GB,2) }
  } | Sort-Object GB -Descending | Select-Object -First 10

This finds the real consumer before you start deleting system files.

What each item actually is

Item	Safe?	Note
Temporary files	yes	apps recreate them
Recycle bin	yes	it is a bin
Downloads	check first	Storage Sense can delete them automatically
Thumbnails	yes	regenerated on demand
Delivery Optimisation files	yes	update cache
Windows Update cleanup	yes	removes old update packages
Previous Windows installation	one-way	no rollback after
WinSxS superseded components	one-way	see below
Hibernation file	configurable	disables hibernation/fast startup
Page file	no	managed by the system

WinSxS: the folder people fear

C:\Windows\WinSxS is not a backup copy of Windows; it is the component store. It contains hard links to files that are in use, so its reported size is far larger than the space it really occupies.

Clean it with the supported command:

Dism.exe /Online /Cleanup-Image /AnalyzeComponentStore
Dism.exe /Online /Cleanup-Image /StartComponentCleanup /ResetBase

AnalyzeComponentStore tells you whether cleanup is worthwhile.
/ResetBase removes the ability to uninstall installed updates. Do not use it on a machine where you may need to roll back a bad patch.

Disk Cleanup (`cleanmgr`) without the guesswork

Storage Sense is the automatic path. cleanmgr is the manual one, and it has two profiles that people mix up:

Mode	Launches	Shows
`cleanmgr`	the standard profile	user-level temp files only
Clean up system files	the elevated profile	Update leftovers, old installs, WinSxS

That second pass is the one with real reclaim, and the one that can cost you a rollback. Run it deliberately:

cleanmgr /lowdisk        # pre-selects the biggest safe items
cleanmgr /sageset:11     # pick items once, stored under this number
cleanmgr /sagerun:11     # run those picks unattended later

/sageset writes its selection to the registry, so /sagerun can be scheduled. Two items deserve a decision rather than a default:

“Previous Windows installation(s)” — deleting Windows.old ends the 10-day window to go back to the old build. The system removes it automatically after that window; deleting early only saves time, not much space you will miss.
“Delivery Optimisation Files” — the local update cache. Safe, but it re-downloads on the next update.

Hibernation and fast startup

hiberfil.sys is usually 40–100% of RAM. Removing it also removes Fast Startup and hibernate:

powercfg /hibernate off   # deletes hiberfil.sys, disables fast startup + hibernate
powercfg /hibernate on    # back on

If the machine is a desktop that never hibernates and has a small SSD, turning it off is a legitimate 8–32GB. On a laptop, think about it — see sleep, hibernate and Fast Startup.

Automate the low-risk part

Settings → System → Storage → Storage Sense: enable it, set Downloads cleanup to “never” if you use that folder, and let it run weekly.

Lab boundary

E1. The cleanup commands are Microsoft-documented; no cleanup was run on the lab VMs for this page, so no freed-space figures are claimed.