
Running out of disk space on Windows is one of the most frustrating things about owning a PC. You install a few apps, take some screenshots, and suddenly your C: drive is glowing red. The good news? You do not need third-party cleaners or risky registry hacks to get your storage back. Windows includes several built-in tools that can free up disk space quickly and safely.
Dealt with a full C: drive more times than I can count. Whether it was a 128 GB laptop with 3 GB free or a desktop where Windows alone was eating 95 GB, the problem is almost never that your files are too large. The real issue? Windows hides a lot of its own disk usage in places most people never check.
Here is the thing. Most guides tell you to run Disk Cleanup and call it a day. That frees maybe 2-5 GB. This article shows the actual steps that recover 15-40 GB or more. These are methods tested across five different machines over the past year.
Disk space cleanup on Windows means identifying and removing files your system no longer needs. Temporary files, cached data, old Windows update files, and replaced system file versions all count. Windows gives you three main tools for this: Disk Cleanup, Storage Sense, and Cleanup Recommendations.
The operating system generates a surprising amount of junk over time. Windows Update leaves behind old versions of system files so you can roll back changes. Every application creates temporary files that often linger forever. Your browser caches pages, images, and scripts. Individually these files are tiny. Collectively they can consume 30-50 GB or more on a PC that hasn’t been cleaned in a year.
Storage Sense is the automated option. It runs on a schedule, removes temporary files, empties the Recycle Bin, and deletes old files from Downloads. Disk Cleanup is the manual tool with deeper access to system files. Cleanup Recommendations lives inside Settings and gives you a categorized view of what you can safely delete.

These methods work on both Windows 10 and Windows 11. Microsoft kept the core cleanup tools consistent across both versions, though the navigation paths differ slightly.
Open Settings > System > Storage. You will see a breakdown of what’s using your drive. Click Cleanup recommendations. Windows scans your drive and groups deletable files into four categories: Temporary files, Large or unused files, Files synced to the cloud, and Unused apps.
From experience helping friends and clients with their laptops, this single screen recovers 15-40 GB on most machines. The biggest chunk is almost always Previous Windows installations. That’s the Windows.old folder left behind after a major update. It can sit at 20+ GB. If your PC has been running smoothly for a few weeks post-update, go ahead and delete it.
Search for Disk Cleanup in the Start menu. Select your C: drive. The initial scan only shows files your user account can delete. Click Clean up system files to see the full list.
The most valuable categories here are Windows Update Cleanup (often 5-15 GB), Delivery Optimization Files, and Temporary Windows Installation Files. All safe to delete as long as your computer is working properly and you don’t plan on uninstalling any updates.
One thing to watch out for: Windows ESD Installation Files. These are compressed installation files used for the Reset this PC feature. Deleting them frees a few gigabytes but removes your ability to reset Windows without downloading installation media. Best to only delete these on machines where a recovery USB drive already exists.
This is where the real space lives. Two system files sit at the root of your C: drive that Windows hides by default. They don’t appear in Disk Cleanup or Storage Sense.
| File | Default Size (16 GB RAM) | What It Does |
|---|---|---|
| hiberfil.sys | ~12 GB | Saves system state when you use Hibernate |
| pagefile.sys | 16-24 GB | Virtual memory overflow for when RAM fills up |
The hibernation file is about 75% of your RAM size. 16 GB of RAM means hiberfil.sys takes up roughly 12 GB. Most people never use Hibernate. They close their laptop lid, which triggers Sleep a completely different function. Open an admin Command Prompt and run powercfg /hibernate off. The file vanishes. Twelve gigs back instantly.
The page file is trickier since you can’t turn it off entirely. But you can shrink it. Go to Advanced System Settings > Performance > Settings > Advanced > Virtual Memory > Change. Uncheck automatically manage paging file size. Set Initial size to 4096 MB and Maximum to 8192 MB. This cuts it from 16-24 GB down to 4-8 GB without affecting stability.
Tested this on a Dell XPS with 16 GB RAM. Combined savings from these two files? 22 GB gone. On a desktop with 32 GB RAM it was 34 GB.
The WinSxS folder at C:\Windows\WinSxS is the component store. Every version of every system file Windows ever installed lives here. After a couple years it balloons to 8-15 GB. Never manually delete anything from this folder. Windows will break.
Use the built-in DISM tool instead. Open Command Prompt as admin and run:
DISM /Online /Cleanup-Image /StartComponentCleanup
This removes superseded component versions. Typically frees 2-5 GB. Adding /ResetBase squeezes out another gig or two but prevents uninstalling any currently installed update. Takes a few minutes and needs a reboot.
Each browser stores cached files in its own folder inside AppData. Chrome, Edge, and Firefox can each accumulate 2-4 GB of cached images, scripts, and page data. On a system with all three browsers that’s up to 12 GB of space consumed by files you’ll never use again.
Press Ctrl+Shift+Delete. Pick Cached images and files. Set the time range to All time. Hit Delete. Repeat for every browser you have installed.
Sometimes you need to see exactly what’s eating your storage. Windows built-in tools are great for cleanup, but they don’t show you a visual map of your drive. Third-party analyzers fill that gap.
WinDirStat is the classic free and open-source option. It scans your drive and displays a treemap where every file is a colored rectangle sized by disk usage. At a glance you can spot the 20 GB ISO file you forgot about or the Steam library you never played.
TreeSize Free offers a more polished folder-size view. WizTree is the fastest option reads the NTFS Master File Table directly and can scan a 1 TB drive in under 30 seconds.
Follow these steps in order. Check your available space after each step before moving to the next.
Step 1: Open Settings > System > Storage > Cleanup recommendations. Review each category and click Clean up for items you don’t need.
Step 2: Run Disk Cleanup as administrator. Check Windows Update Cleanup, Delivery Optimization Files, and Temporary Windows Installation Files.
Step 3: Disable Hibernation. Admin Command Prompt. Type powercfg /hibernate off. Enter. The file disappears. Space comes back equal to 75% of your RAM.
Step 4: Shrink the Page File. Advanced System Settings > Performance > Advanced > Virtual Memory > Change. Set 4096 MB initial and 8192 MB maximum.
Step 5: Clean WinSxS. Run DISM /Online /Cleanup-Image /StartComponentCleanup in admin Command Prompt. Reboot.
Step 6: Clear browser caches. Ctrl+Shift+Delete in Chrome, Edge, Firefox. Cached images and files for All time.
Step 7: Check your screenshots folder. Win+Print Screen silently saves a PNG to Pictures\Screenshots on every press. Thousands can accumulate before you notice.
Step 8: Use a disk space analyzer. Download WinDirStat or TreeSize Free. Scan and look for large files to move or delete.
| Tool Type | Pros | Cons |
|---|---|---|
| Windows Built-In (Storage Sense, Disk Cleanup) | Free, safe by default, no installation needed | Limited visibility, can’t find large personal files |
| Disk Space Analyzers (WinDirStat, TreeSize) | Full visibility, visual treemap, finds everything | Requires download, can overwhelm with data |
| Third-Party Cleaners (CCleaner, BleachBit) | One-click cleanup, registry tools | Risk of deleting important files, privacy concerns |
My take: use built-in Windows tools for routine cleanup and install a disk space analyzer for the deeper investigations. Skip the one-click PC cleaners. They often delete files you need or bundle adware.
Almost everything in Disk Cleanup is safe to delete, with one exception: Windows ESD Installation Files. Those are the compressed installation files used for the Reset this PC feature. Deleting them frees a few gigabytes but removes your ability to reset Windows without downloading installation media. As How-To Geek explains, you should keep these unless you are really hurting for space.
Chances are the hibernation file (hiberfil.sys) and page file (pagefile.sys) are eating most of your space. On a machine with 16 GB of RAM, these two files alone can consume 28-36 GB. Neither shows up in normal file browsing or Disk Cleanup. Check the root of C: with hidden files turned on and you will likely find the culprit.
Enable Storage Sense to run automatically during low disk space and you may never need to manually clean again. For deeper maintenance, run the DISM component store cleanup every 3-4 months. A full manual cleanup using the steps above works well once every 6-12 months depending on how much software you install and uninstall.

Freed up 30 GB today? Great. But it will fill up again if you don’t set up automatic maintenance. Enable Storage Sense in Settings > System > Storage. Set it to run during low free disk space. Configure it to delete Recycle Bin files after 30 days and remove temporary files apps aren’t using.
Run DISM maintenance every few months. Admin Command Prompt: DISM /Online /Cleanup-Image /StartComponentCleanup. Also run DISM /Online /Cleanup-Image /AnalyzeComponentStore to check whether the WinSxS folder needs cleaning.
The honest truth? You almost never need to buy more storage or reformat your drive. Windows ships with all the tools required to keep your disk healthy. The space is there. You just have to know where to look.