Why a full drive causes trouble
A drive that is almost full can make a computer feel slow, stop updates from installing and cause programs to fail when they need room to save work. Operating systems also use free space for temporary files and for the swap area they rely on when memory runs short. There is no single magic percentage, but keeping a healthy margin free, often cited as somewhere around a tenth to a fifth of the drive, is a sensible habit.
Find out what is using the space first
Guessing wastes time. Look before you delete.
- Windows: open Settings, then System, then Storage. It breaks usage into categories such as apps, temporary files, documents and pictures.
- macOS: open System Settings, then General, then Storage. It shows a similar category bar.
- Folder-size viewers: free tools exist that draw your drive as a map of boxes sized by how much room each folder takes. Download one only from the developer’s official site, because fake “cleaner” programs are a common way to get unwanted software onto a machine.
Often a few things account for most of the space: video files, old downloads, a large photo collection, game installations or backups of a phone. Starting with the biggest items gives the best return for the least risk.
Safe places to start
These are generally low-risk, though it is still wise to glance at what is there before emptying anything.
The recycle bin or trash. Deleted files usually sit here and still take up room until you empty it. How file deletion works is worth understanding: emptying the bin releases the space, but it also removes your easy way back, so check it first.
The downloads folder. It tends to collect installers, receipts, zip files and documents you opened once. Sort by size and clear what you no longer need. Installers for programs already installed can normally be removed, since you can download them again if required.
Temporary files. Both Windows and macOS offer built-in cleanup for temporary files. On Windows, the Storage settings page lists temporary files and, in recent versions, offers Storage Sense, which can clear them on a schedule. These are files the system and programs have marked as disposable.
Browser caches. Browsers store copies of pages and images to load sites faster. Clearing the cache frees space, though pages may load slightly slower the first time afterwards. You do not need to clear saved passwords or logins to do this, so pick only the cache option.
Unused applications. Uninstall programs and games you no longer use, using the system’s own uninstall option rather than just deleting folders. Games and creative software are often the largest.
Large personal files
After the easy items, look at your own files, which only you can judge.
- Videos and photos. These are usually the biggest items. Consider moving older ones to an external drive or to cloud storage, and confirm they opened correctly from the new place before deleting the originals. If you keep a large photo library, deciding what is a true duplicate or a blurry near-copy can free a lot of room.
- Duplicates. Duplicate-finding tools exist, but review their suggestions by hand; automatic deletion can remove the wrong copy.
- Old backups of phones and devices. These can be several gigabytes each and are easy to forget.
- Large archives. Compressing rarely used files into archives can save some space. File compression helps most with documents and less with media that is already compressed, such as most photos and videos.
Things to leave alone
Some files look large and tempting but are not yours to remove.
- Folders inside the system directory, such as the Windows folder or the macOS system and library areas. Deleting parts of these can stop the computer from starting.
- Program folders, deleted by hand instead of uninstalled. This often leaves a broken installation.
- The hibernation file and the page or swap file. They can be managed through system settings if you understand the trade-offs, but removing them manually is not advised.
- Anything you do not recognise in a system folder. Searching for the exact file name first is a cheap safeguard.
Be cautious about advertisements or pop-ups that claim your computer is full of junk and offer a quick fix. Genuine cleaners rarely free much more than the built-in tools do, and some pose as such tools to push paid software or worse.
Make it last
Before a big clear-out, make sure anything irreplaceable is copied somewhere else first. Mistakes are easier to reverse if you have a copy.
Then reduce the chance of a repeat:
- Turn on automatic temporary-file cleanup if your system offers it.
- Review the downloads folder every month or two.
- Keep large media on a separate drive or in cloud storage if you have a smaller internal drive.
- Use sensible folder names and structure so old material is easier to find, a habit covered under file organization.
If you have done all this and the drive is still full, the honest answer may be that the drive is too small for how you use the computer. An external drive is the cheapest fix, and replacing the internal drive with a larger solid state drive is an option on many, though not all, machines.