How to Free Up Disk Space on Your PC
When a drive fills past about 90%, a computer slows noticeably — there's simply no room left for it to work efficiently, updates start to fail, and you get that dreaded "low disk space" warning at the worst moment. The good news is that reclaiming space is usually quick and free, and you rarely need to delete anything you actually care about. Here's how to do it safely on Windows and Mac — and what to leave well alone.
Why a full drive slows everything down
Your computer uses free disk space as breathing room — for temporary files, virtual memory and the housekeeping that keeps things smooth. When that space runs out, the machine has nowhere to work, so everything from opening apps to installing updates grinds. Keeping 10–15% of the drive free isn't fussiness; it's what lets the computer perform as it should.
1. Clear the easy stuff first
- Empty the Recycle Bin / Trash. Deleted files sit there taking up space until you do — often gigabytes' worth.
- Remove temporary files. Windows Storage Sense and the macOS storage tools clear caches and system junk safely; this is a good, risk-free first sweep.
- Uninstall programs you no longer use, especially large games, trials and that software you installed once and forgot.
- Empty your Downloads folder. It's quietly full of installers and files you finished with months ago.
2. Find the big space-eaters
Rather than nibbling at small files, target the giants. Both Windows (Settings → System → Storage) and macOS (Settings → General → Storage) have built-in tools that show what's using the most room, so you can go straight for it. The usual culprits are photos, videos, downloaded media and old backups. Two that catch people out: old phone backups stored on the computer, and the leftover Windows.old folder a major update leaves behind, which can be several gigabytes on its own.
3. Move, don't just delete
For things you want to keep but rarely touch — photo libraries, old projects, video — move them to an external drive or the cloud rather than deleting them. The golden rule here is non-negotiable: make sure anything important still has a backup before you remove the only copy. It's heartbreakingly easy to "tidy up" your way into losing irreplaceable photos.
4. Tackle the sneaky space hogs
A few less-obvious culprits are worth checking. Email apps can cache years of attachments locally. Cloud-storage apps sometimes keep a full copy of everything on the drive — switching on "online-only" or "optimise storage" can free huge amounts. And on a Mac, the "Other" storage category is often old caches and downloads the built-in tools can clear. A few minutes here often frees more than hours of deleting individual files.
What not to delete
Be cautious about two things. First, steer clear of "free up space" pop-ups and aggressive third-party "cleaner" apps that promise to find gigabytes of junk — some delete things you need, and others bundle adware (see do you need antivirus?). Second, don't go hunting through system folders deleting files you don't recognise; the built-in tools already remove what's genuinely safe to remove. When in doubt, leave it alone.
Set your computer to manage space for itself
Once you've done a clear-out, turn on the tools that stop the problem coming back. On Windows, Storage Sense (Settings → System → Storage) can automatically empty the recycle bin and clear temporary files on a schedule, so junk never piles up again. On a Mac, the "Optimise Storage" options keep older files in iCloud and only download them when needed, and "Empty Trash automatically" removes items after 30 days. Setting these up takes a couple of minutes and means you'll rarely see a low-space warning again. It's the difference between a one-off tidy and a drive that looks after itself — and on a machine used by less technical family members, it quietly heads off the slow, full-drive crawl before it ever starts.
Still cramped? Consider an upgrade
If you're forever running out of room no matter how much you clear, the real answer is a bigger drive — and if your machine still has an old mechanical hard drive, upgrading to a larger SSD solves the space problem and makes the whole computer dramatically faster at the same time. It's one of the best-value upgrades there is. Our computer repair team can fit one and migrate all your data across so nothing is lost — with a clear quote first.