How to Free Up Disk Space on Windows 11 (2026)
Short answer: Open Settings, System, Storage, Temporary files, tick everything except Downloads, and Remove files — on a drive untouched for a year this alone frees 15-40 GB, and the biggest chunk is usually Previous Windows installations (Windows.old) sitting at 20+ GB after a major update. For more, clear WinSxS with DISM, disable hibernation, and shrink the page file.
Go to Settings, System, Storage, Temporary files. Check everything except Downloads — that’s your actual Downloads folder, not cache. Hit Remove files. On a machine that hasn’t been cleaned in a year I usually get 15-40 GB back from this one screen. The biggest chunk is almost always Previous Windows installations — Windows keeps a full backup in Windows.old after major updates and just leaves it sitting there at 20+ GB.
That’s the easy part though. The real space is hiding in files Windows doesn’t even show you.
The Two Files You Can’t See
Turn on hidden files and system files in File Explorer — View tab, check both boxes — and look at the root of C:. hiberfil.sys and pagefile.sys. On a 16 GB machine these two are eating 25-45 GB between them, and neither shows up in Disk Cleanup or that nice Storage breakdown in Settings.
Hibernation file is about 75% of your RAM — 12 GB on a 16 GB machine, permanently camped on your C: drive whether you’ve ever used hibernate in your life. Most people close the laptop lid, which is Sleep. Completely different thing. If you don’t specifically hibernate: admin Command Prompt, powercfg /hibernate off, file vanishes, twelve gigs come back instantly. If you change your mind later, powercfg /hibernate on brings it back.
That also kills Fast Startup, which uses hibernation under the hood. On an SSD the boot difference is about two seconds. On a hard drive it’s more noticeable, but if you’re running a hard drive in 2026 and worrying about disk space, getting an SSD should be higher on the list.
Page file is worse because you can’t just turn it off. Virtual memory — Windows’ overflow lot when RAM fills up. Default on a 16 GB machine is somewhere between 16 and 24 GB. I’ve seen 32 GB machines with a 32 GB page file. One file, 12% of a 256 GB drive. You can shrink it though. Advanced system settings, Performance, Settings, Advanced tab, Virtual memory, Change. Uncheck automatic management, set Initial to 4096 and Maximum to 8192. Cuts a 20-ish GB file to 4-8 GB. Don’t go below 4096 — Chrome with thirty tabs eats through page file faster than you’d think and Windows just locks up with no warning at all.
Also check your Pictures\Screenshots folder — Win+Print Screen silently saves a PNG on every press, and people who don’t realize it pile up thousands of screenshots without knowing.
Had a client with a 128 GB eMMC laptop. Three gigs free, barely anything installed — two browsers, Spotify, that’s it. Between hiberfil.sys, pagefile.sys, WinSxS, and temp files, Windows itself was consuming 95 GB of 128. At some point that stops being a cleanup problem. And don’t partition a drive that small — you’ll just make two partitions that are both too small to use.
WinSxS
C:\Windows\WinSxS. Component store. Every version of every system file Windows has ever installed lives here so it can roll back individual components. After a couple years it balloons to 8-15 GB. Do not manually delete anything from it — Windows will break.
DISM /Online /Cleanup-Image /StartComponentCleanupFrees 2-5 GB. Add /ResetBase at the end to squeeze another gig or two — prevents you from uninstalling any currently installed update, but I’ve never met anyone who actually does that. Takes a few minutes, needs a reboot.
The Usual Suspects
Ctrl+Shift+Delete in your browser, pick cached images and files, set to All time. Probably 2-4 GB per browser, and if someone runs Chrome and Edge and Firefox — more common than you’d think — that’s up to 12 GB across three separate cache folders in AppData. Our cache clearing guide covers all the other caches Windows hoards too — DNS, icon cache, Store cache.
Sort your installed apps by size — our uninstall guide covers the stubborn ones that won’t remove cleanly. There’s always a forgotten trial of something from two years ago sitting at 2 GB. Games are the big ones though — a single modern title is 50-150 GB. Move your Steam library to a second drive instead of uninstalling everything. No redownload needed.
Windows Update cache in C:\Windows\SoftwareDistribution\Download — stop the service with net stop wuauserv, delete everything inside the Download folder, restart with net start wuauserv. Usually another 1-5 GB.
It’s Going to Fill Up Again
Clean everything, get 50 GB back, two months later you’re in single digits again. Cumulative updates grow larger each month. Browser cache rebuilds the second you open a tab. If OneDrive is set to “keep all files on this device,” it’s silently mirroring everything from the cloud onto your local drive for no reason — switch to Files On-Demand.
The permanent fix for a 256 GB drive that won’t stay clean is usually admitting 256 wasn’t enough. 1 TB NVMe is $60-80 and cloning takes about an hour. Or move your Documents and Pictures to a second drive — right-click the folder, Properties, Location tab, Move. Windows redirects transparently and C: stops being the dumping ground for everything.
If the drive isn’t just full but also noticeably slow, that might be a failing drive — check the health before spending time on cleanup. If you’d rather have someone do the whole thing, we remote in and usually recover 30-80 GB in about half an hour.
Frequently Asked Questions
What takes up the most hidden space on Windows 11?
Three things that most people never check: temporary files from Windows Updates (often 15-40 GB on machines that haven't been cleaned in a year), the hibernation file hiberfil.sys (roughly 75% of your RAM size — 12 GB on a 16 GB machine), and the page file pagefile.sys (defaults to 16-24 GB on a 16 GB RAM machine). These three alone can consume 40-75 GB and none of them show up in your normal file browsing.
Is it safe to delete everything in Disk Cleanup?
Almost everything, yes. The only category worth thinking twice about is 'Previous Windows installations' — deleting that removes your ability to roll back to the previous Windows version, which Microsoft keeps for ten days after a major update. If your machine is running fine after the update, delete it and reclaim 20+ GB. Everything else — temp files, Delivery Optimization, thumbnails, shader cache — is completely safe to remove.
Can I delete the WinSxS folder to free space?
Never delete WinSxS manually — Windows will break. But you can safely shrink it using the built-in DISM tool. Open Command Prompt as admin and run DISM /Online /Cleanup-Image /StartComponentCleanup which removes superseded component versions. This typically frees 2-5 GB. The more aggressive /ResetBase flag saves extra space but prevents uninstalling any currently installed updates.
How much page file do I actually need?
For a machine with 16 GB of RAM, set the page file to 4096 MB initial and 8192 MB maximum. That cuts it from the default 16-24 GB down to 4-8 GB, freeing 12-16 GB instantly. Don't go below 4 GB on any machine — Chrome with thirty tabs, Photoshop, and video editors genuinely need page file space even with plenty of physical RAM.
Why does my disk keep filling up after I clean it?
Three ongoing consumers: Windows cumulative updates grow in size over time and each one is larger than the last, browser cache rebuilds immediately as you browse, and application data grows continuously (Outlook data files, Spotify offline cache, Discord cache). If you have OneDrive set to 'keep all files on this device,' switch to Files On-Demand so files only download when you open them. For a 256 GB drive that keeps filling up, the permanent fix is usually cloning to a 1 TB SSD ($60-80) or moving your user folders to a second drive.