A computer running out of storage is one of the most common reasons a machine starts feeling sluggish. When your drive fills up, Windows and macOS both struggle: the system needs temporary disk space to run apps, process files, and install updates, and when that space disappears, performance drops fast. The good news is that most storage problems are fixable without buying new hardware.
What actually eats your disk space
Before deleting anything, it's worth knowing what's actually taking up room. Most people are surprised to discover the culprits aren't what they expect.
On a Windows PC, temporary files are almost always the biggest offender. Windows creates temp files constantly as you work, and it doesn't always clean them up. System restore points and old Windows Update files can quietly consume 10–30 GB on their own. On a Mac, the equivalent problem is application caches and old iOS backups stored locally by iTunes or Finder.
Downloads folders are another common cause. Files you downloaded once and forgot accumulate quickly. Video files are the worst offenders since a single downloaded film can be 4–8 GB.
Duplicate photos are a third major source. If you've ever imported a photo library more than once, or backed up a phone multiple times without cleaning up, you may have thousands of identical images on disk.
How to check how much space you have left
On Windows 11, open Settings, go to System, then Storage. Windows will show you a breakdown of exactly what's using space: apps, temporary files, documents, and other categories. On a Mac, click the Apple menu, choose About This Mac, then Storage. Both give you a visual overview in under a minute.
If you're on Windows and your drive is under 10% free, your computer is already in the zone where performance degrades noticeably. Under 5% free and you'll likely see crashes, failed updates, and apps refusing to open.
The fastest ways to free up space on Windows
Windows has a built-in tool called Disk Cleanup that handles the most common junk files. Search for it in the Start menu, select your main drive (usually C:), and run it. Click "Clean up system files" to include Windows Update remnants. On most systems, this recovers between 2 GB and 15 GB with a single click.
Storage Sense is the more automated version. You'll find it inside Settings under System and then Storage. Turn it on, and Windows will automatically delete temporary files and empty the Recycle Bin on a schedule you choose. It's worth enabling even after you've done a manual clean.
After that, the highest-impact manual steps are:
- Uninstall apps you don't use (Settings, then Apps, then Installed Apps on Windows 11)
- Empty the Downloads folder after reviewing its contents
- Move large video and photo files to an external drive or cloud backup
The fastest ways to free up space on a Mac
Apple's built-in storage management tool is the right starting point. Go to the Apple menu, About This Mac, Storage, and click Manage. You'll see four options: Store in iCloud, Optimize Storage, Empty Trash Automatically, and Reduce Clutter.
"Optimize Storage" removes films and TV shows you've already watched from Apple TV and keeps only recent email attachments locally. It's safe to enable. "Reduce Clutter" shows you large files sorted by size, which is useful for spotting things you forgot you downloaded.
Beyond the built-in tools, check your Applications folder for apps you installed years ago and never opened again. Also check ~/Library/Application Support/ for leftover data from apps you've already deleted. Uninstalling a Mac app by dragging it to the Trash often leaves several hundred megabytes of support files behind.
When clearing junk files isn't enough
If you've cleaned up temporary files, emptied downloads, and uninstalled unused apps and your drive is still nearly full, the problem is usually one of three things: a genuinely large media library, a drive that was undersized from the start, or a hidden system issue causing runaway file growth.
Log files can grow unexpectedly large when software is crashing repeatedly in the background. On Windows, check C:\Windows\Logs and C:\ProgramData for oversized folders. On a Mac, use the Console app to look for repeated crash reports. A slow computer and a full disk often share the same underlying cause, so fixing one frequently fixes the other.
For a media library that's simply too large for your internal drive, the right answer is usually an external SSD or a network-attached storage device rather than more deletion. Modern external SSDs are compact, fast enough for video editing, and cost far less than upgrading internal storage on a laptop.
Should you upgrade your storage?
On a desktop PC, adding a second drive is straightforward and inexpensive. A 1 TB SSD costs well under $100 in Australia and can be installed in an afternoon. On a laptop, it depends on the model: some allow easy SSD swaps, others have storage soldered to the motherboard.
MacBooks released from 2016 onwards have non-upgradeable storage. If your MacBook's internal drive is too small, your options are iCloud Drive, an external drive, or upgrading to a newer machine. The repair vs replace decision is worth thinking through carefully before spending money on either option.
If you're not sure what your computer supports, a technician can check in minutes. Remote support is often enough to diagnose the problem, run a full storage audit, and walk you through the right next step without needing to bring your machine in anywhere.
Keeping storage under control going forward
The best approach is a light monthly habit rather than an annual emergency clean. Turn on Storage Sense on Windows or Optimize Storage on Mac. Set your Downloads folder to auto-delete after 30 days. Keep one organised folder for files you're actively working on, and move everything else to cloud or external storage as a matter of routine.
A drive that stays above 15% free runs noticeably better than one that sits at 2%. That gap doesn't require more hardware. It just requires a consistent habit and the right tools switched on.