How to Free Up Disk Space on Windows 11: Diagnose First, Then Delete in the Right Order
CodexFuse Team · 2026-10-26T18:05:13.850Z · 12 min read
Learning how to free up disk space on Windows 11 starts with one habit most guides skip: look before you delete. The "low disk space" warning tells you the C: drive is nearly full, but it never tells you what filled it — and the fix for a drive full of games is different from the fix for a drive full of temporary files or a forgotten Windows.old folder. The order in this guide is diagnose first, then delete in the right order, so you get the gigabytes back without breaking anything. If the real problem is that the whole machine feels slow rather than full, our guide to speed up a slow laptop covers the rest of the fix.
How do I free up disk space on Windows 11?
To free up disk space on Windows 11, open Settings > System > Storage to see what is using the space, then work in this order: run Cleanup recommendations, delete temporary files, empty the Recycle Bin, uninstall apps and games you no longer use, and move large files to another drive or to OneDrive. Turn on Storage Sense last, so Windows keeps the drive tidy for you automatically.
- Diagnose. Open Settings > System > Storage and read the category bar for your C: drive. The biggest category decides what you do next.
- Clean what Windows offers. Use Cleanup recommendations, then the Temporary files page. These are the safest gigabytes on the machine.
- Empty the Recycle Bin. Deleted files still take up space until the bin is emptied, so check it holds nothing you still need, then empty it.
- Remove the big stuff you chose. Sort Installed apps by size and uninstall what you no longer use. Move large videos, installers, and old projects off the system drive.
- Automate it. Turn on Storage Sense with safe schedules, so temporary files and old Recycle Bin items are cleared without you remembering.
How much free space should you keep on the C: drive?
Keep at least 20 GB free on your C: drive, and more before a big Windows update. That is the figure SupportYourTech recommends in its Windows 11 cleanup guide, updated October 21, 2026: Windows needs room to download and unpack updates, and a nearly full drive can make your PC slower. The number is a floor, not a target — if you are below it, treat the cleanup below as urgent rather than optional.
There is a second reason to keep headroom. Windows enables Storage Sense on its own when the operating system needs space for a task such as installing a feature update, even if you left the feature switched off, according to Windows Central. That automatic cleanup only removes temporary files, so it will not save a drive that is full of your own files. The 20 GB rule is what keeps you out of that corner in the first place.
What is taking up space on my PC?
Open Settings > System > Storage and look at the bar for your C: drive, then at the categories below it: Apps, Temporary files, Documents, Pictures, Videos, Other, and System & reserved. Select "Show more categories" to see everything. This one screen answers the question, and the biggest category tells you which section of this guide to run first.
| Category is biggest | What it usually means | Do this first |
|---|---|---|
| Temporary files | Update leftovers, caches, and files Windows no longer needs | Cleanup recommendations, then the Temporary files page |
| Apps | Games and creative apps, often tens of gigabytes each | Sort Installed apps by size and uninstall what you no longer use |
| Documents or Videos | Your own files: installers, archives, old projects, recordings | Sort by size in File Explorer and move or delete what you choose |
| Other | Installers, virtual machines, game recordings, folders Windows could not classify | Open File Explorer, sort folders by size, and inspect the biggest ones |
| System & reserved | Windows itself, the previous Windows version, restore points | Remove the previous Windows installation if you will not roll back |
If the drive keeps filling up again after a cleanup, check the same page a few days later and see which category grew. SupportYourTech lists the usual culprits as game updates, OneDrive syncing, and video recordings. That pattern matters: a category that grows on its own is a setting to change, not a file to delete again.
How to delete temporary files in Windows 11
In short, this is how to delete temporary files Windows 11 keeps: open the Temporary files page, check what you want gone, and remove it. Temporary files are the safest space to reclaim, and Windows gathers them in one place. Open Settings > System > Storage, select Temporary files, wait for Windows to finish scanning, check the types you want to remove — Temporary files, Thumbnails, Delivery Optimization Files, Windows Update Cleanup, and the Recycle Bin are the usual ones — and select Remove files. Some items, such as leftovers from Windows updates, need administrator rights to remove; if they are grayed out or Windows asks for an administrator, leave them alone, as SupportYourTech advises.
There is one checkbox to read before you tick it. The Downloads item in the Temporary files list deletes everything in your Downloads folder, and Windows does not check what is in it first — it may hold files you meant to keep. Windows Central gives the same warning for the Downloads item in Disk Cleanup. If your Downloads folder is a working folder rather than a junk drawer, skip that checkbox and sort through it by hand in File Explorer instead.
Deleting temporary files is also the step to take when Windows Update says there is not enough space. Free up what you can first, then connect a USB drive if Windows Update asks for one — it uses the drive as temporary space during the update, according to SupportYourTech.
What is Windows 11 Storage Sense?
Windows 11 Storage Sense is the built-in feature that deletes temporary files and old Recycle Bin items automatically, so you do not have to remember to do it. It is the automation step, not the cleanup itself: turn it on after you have done the one-time cleanup above, and it keeps the drive from filling up again.
To set it up, open Settings > System > Storage, turn on the Storage Sense toggle, then select Storage Sense to change how it works. Under "Run Storage Sense", choose when it runs — every day, every week, every month, or during low free disk space, which Windows Central lists as the recommended setting. Turn on "Automatic User content cleanup" and choose how long files stay in the Recycle Bin: Norton notes the options run from 1 to 60 days. Leave the Downloads setting on Never if you use Downloads as a working folder, as SupportYourTech recommends, and choose how long OneDrive content stays locally available before it becomes online-only.
Two Storage Sense behaviors surprise people. First, as noted above, Windows can enable it on its own when the operating system needs space for a feature update, so do not be surprised if it is already on. Second, it only removes files older than the time you set. If Storage Sense deleted nothing, open its settings and select "Run Storage Sense now" at the bottom of the page.
Disk Cleanup Windows 11: the classic tool
Disk Cleanup is the older tool that does the same job as the Temporary files page, and it is still there in Windows 11. Type "Disk Cleanup" in the Start menu search and press Enter, choose the C: drive, and check the file types you want to delete — Temporary files, Delivery Optimization Files, and the Recycle Bin are the usual picks. Each category shows how much space deleting it will free. Click OK, then confirm with Delete Files.
For a deeper clean, click "Clean up system files" in the same window. That option lets you delete unused system files, including the previous Windows installation, which can free up even more space. PCWorld's walkthrough of the tool, published October 20, 2025, recovered 1.1 GB of files from the author's PC with a single run — a useful sense of scale for what the classic tool finds on a machine that has never been cleaned.
One caution from the same walkthrough: Disk Cleanup is safe to use because it is designed to delete only files that are unnecessary, leaving your documents and applications intact. That safety applies to what it lists. It does not apply to the Windows folder, Program Files, or anything else you go looking for by hand — those are covered in the safe-to-delete table below.
How to find and remove large files and unused apps
When the Storage page says Apps is the biggest category, the fix is uninstalling, not deleting files one by one. Open Settings > Apps > Installed apps, change "Sort by" to "Size (large to small)", and the biggest apps rise to the top. Games and creative apps are often the largest, and some desktop apps need administrator rights to uninstall. Click the three dots next to an app you no longer use and select Uninstall.
When Documents, Videos, or Other is the biggest category, the fix is sorting by size. Open File Explorer, go to a folder such as Videos, Pictures, or Downloads, select View > Details, then click the Size column heading to sort largest first. Videos, photo libraries, and old backups can take tens of gigabytes each, according to SupportYourTech. Delete what you no longer need, or move it to an external drive: connect a USB drive or external hard drive, select the files, select Cut, open the external drive, and select Paste.
Two moves cost nothing and save real space. First, if you use OneDrive, right-click a OneDrive folder or file in File Explorer and select "Free up space" — the file stays in OneDrive and downloads again when you open it, as long as you are online. Second, if your PC has a second drive, go to Settings > System > Storage > Advanced storage settings > Where new content is saved, and send new documents and new apps there so the C: drive stops filling up in the first place.
What is safe to delete — and what is not?
The rule is simple: delete what Windows offers you, and what you put there yourself. Never delete system files, the Windows folder, or Program Files by hand. SupportYourTech's guide is blunt about the same point: registry cleaners and "PC cleaner" apps rarely free much space and can cause problems, and Windows' own tools are enough.
| Safe to delete | Do not delete |
|---|---|
| Temporary files Windows lists in Settings > System > Storage | Files in the Windows folder (usually C:\Windows) or Program Files |
| Recycle Bin contents, once you have checked nothing in it is still needed | The paging file, hibernation file, or restore points by hand |
| Apps and games you installed and no longer use | The previous Windows installation if you might still roll back (about 10 days after an upgrade) |
| Downloads you have checked by hand — never the whole folder blindly | Files in Downloads you have not looked at yet |
| Browser cache (cached images and files only — keeps you signed in) | Anything a "PC cleaner" app flags that Windows itself does not list |
| Old user accounts nobody uses, after copying anything they need | Files belonging to another user account before copying them |
The previous Windows installation deserves a line of its own. For about 10 days after an upgrade, Windows keeps your previous version so you can go back, and it can take many gigabytes. If you do not plan to go back, it is listed in Cleanup recommendations as your previous Windows installation. Once it is removed, you cannot return to the old version — so only delete it when you are sure.
One more warning, from the topic's own research notes and worth repeating here: back up before NTFS compression. Compressing a whole drive can save space, and Microsoft lists it as a way to free space for updates, but it rewrites files across the drive and takes a long time on a full one — WindowsForum's guide notes the time runs from minutes for a small data partition to several hours for a large, full drive, and advises plugging a laptop into power first. It is an advanced option for when the safe steps above were not enough, not a first move. Our guide to back up your website covers the backup habit in general, and the same principle applies to your PC: copy what matters before you compress or delete anything you cannot get back.
What to do when the drive fills up again
If the drive fills up again within days, the problem is not a file you missed — it is a process that keeps writing. Check Settings > System > Storage again and see which category grew. Game updates, OneDrive syncing, and video recordings are the common causes SupportYourTech names. A game launcher downloading a 40 GB update will undo a careful cleanup in one afternoon, and the fix is a setting — move the game library to another drive, or pause automatic updates — not another round of deleting.
GridinSoft's guide to freeing space safely gives the same order this article uses, and it is worth keeping as a rule of thumb: check Storage usage first, remove temporary files, empty the Recycle Bin, uninstall large unused apps, move personal videos and photos off the system drive, and only then consider advanced options such as hibernation, restore points, or external storage. If free space disappears again after cleanup, check for Windows Update leftovers, a runaway Temp folder, backup or sync loops, or malware before deleting more files.
When none of that applies and the drive is simply too small, the honest answer is a bigger drive or an external one. A 128 GB system drive cannot hold modern games, a photo library, and Windows updates at the same time, no matter how often you clean it. Move what you can to external storage, point new content at the second drive, and keep the 20 GB of headroom on the C: drive. That is how to free up space on Windows without losing a file you need — and it is the habit that keeps the warning away for good. If the slow part turns out to be your website rather than your PC, our guide to speed up your website applies the same diagnose-first idea to the other side of the screen.
Sources
SupportYourTech — How to Free Up Disk Space in Windows 11 (9 Safe Ways), updated October 21, 2026 (Cleanup recommendations first, Storage Sense schedules, the Downloads warning, the 20 GB rule, the previous-Windows-installation 10-day window, the registry-cleaner warning, the still-filling-up causes). Windows Central — How to free up disk space on Windows 11 (Storage Sense setup and the auto-enable note, Cleanup recommendations steps, Disk Cleanup and system restore points, OneDrive Files On-Demand, uninstalling by size). PCWorld — How I instantly free up hard drive space in Windows 11, October 20, 2025 (Disk Cleanup walkthrough, 1.1 GB recovered in the example). Norton — 11 ways to free up disk space on PC and Mac (Recycle Bin and Storage Sense schedules, the 1/14/30/60-day intervals). GridinSoft — Free Up Disk Space on Windows 11/10 Safely (the safe cleanup order, the investigate-first rule when space disappears again). WindowsForum — How to Use NTFS Compression in Windows 11 and 10 to Free Drive Space Safely (NTFS compression steps, files in use not compressing, minutes-to-hours timing, plug the laptop in first).
Frequently Asked Questions
What is taking up space on my PC?
Open Settings > System > Storage and read the category bar for your C: drive. The biggest category — Apps, Temporary files, Documents, Videos, or Other — tells you what filled it. Select "Show more categories" to see everything, and sort folders by size in File Explorer when the "Other" category is the biggest.
Is it safe to use Cleanup recommendations?
Yes, as long as you review what is checked. Windows only suggests files it considers safe to remove, but you decide which personal files to delete. The one checkbox to read carefully is Downloads: Windows does not check what is in it, and it may hold files you meant to keep.
Can I delete the Windows.old folder?
Yes, but only when you are sure you will not roll back. For about 10 days after an upgrade, Windows keeps your previous version so you can go back, and it can take many gigabytes. It is listed in Cleanup recommendations as your previous Windows installation. Once it is removed, you cannot return to the old version.
Does deleting files make my PC faster?
It helps when the drive is nearly full. Beyond that, free space makes little difference to speed, as SupportYourTech notes in its guide. If the machine is slow with plenty of space left, the cause is something else — startup programs, a failing drive, or not enough memory — and deleting more files will not fix it.
How do I free up space on Windows without deleting my files?
Move them instead of deleting them. Right-click OneDrive files in File Explorer and select "Free up space" to keep them online-only, move large videos and installers to an external drive, and point new content at a second drive in Settings > System > Storage > Advanced storage settings > Where new content is saved. NTFS compression is a last resort, and only after a backup.