Why does my computer say it is full when I have deleted everything?
The missing space is in snapshots, restore points, update caches, the recycle bin, the hibernation file and system reserves. Where each one lives and what is safe to reclaim.
- Difficulty
- beginner
- Time
- 40 min
- Read
- 4 min
- Safety
- caution
Short answer
Your own files are usually a minority of a full drive. Check, in order: the recycle bin or trash, which still occupies space; local snapshots and restore points, which hold previous versions of everything; the update and installer cache, which can be many gigabytes after a major upgrade; the hibernation file, which is as large as your memory; and a system-reserved area you cannot touch. Use the operating system's own storage tool rather than a third-party cleaner.
It is genuinely disorienting to delete a hundred gigabytes and watch the free space barely move. The explanation is always one of a short list, and the diagram sets them out as the stack they actually form.
Safety
Step by step
- Empty the recycle bin or trash first.Deleted files still occupy the drive until the bin is emptied. This alone explains a large proportion of these cases, and it is the thing people are most certain they have already done.
- Open the system's own storage overview.Windows' storage settings and macOS's storage management break the drive down by category and are far more accurate than a folder-by-folder hunt. Start here rather than with a third-party tool.
- Look at snapshots and restore points.macOS keeps local snapshots of Time Machine backups on the drive itself, which can occupy a large amount and is why a Mac reports space as "purgeable". Windows restore points do the same job. Both are released automatically as space runs short, but you can reduce the allocation deliberately if you need the room now.
- Clear the update and installer cache.After a major system upgrade, the previous installation is kept for a limited period so you can go back, and it is often twenty gigabytes or more. The disk clean-up tool has a specific option for previous installations. Removing it forfeits the ability to roll back.
- Check the hibernation file.On Windows it is as large as the installed memory and sits at the root of the system drive. If you never hibernate and are short of space, it can be disabled — at the cost of hibernation and of fast startup.
- Find the large folders that are not yours.A disk usage visualiser shows the drive as a map of nested folders sized by what they hold, and it finds things no category view will: an application's cache, a virtual machine file, a games library, an old backup of a phone, a downloads folder with a year of installers.
- Check the mail and photo applications.Locally cached email with attachments and a photo library set to keep originals are among the largest folders on a typical machine, and neither appears where people look. Both can usually be set to keep less locally.
- Accept the reserved portion.Part of the drive is reserved by the system for updates and its own working space, and part of the apparent shortfall is simply the difference between decimal and binary counting. Neither is recoverable and neither is a fault.
If it doesn't work
Mac shows tens of gigabytes as purgeable
Cause: Local Time Machine snapshots and caches — Fix: The system releases them automatically when something needs the space, so it is usually not a problem to solve. If you need the space immediately for a large copy, reducing snapshot retention through the backup settings is the supported route.
Windows drive full straight after a feature update
Cause: The previous installation kept for the rollback period — Fix: Use disk clean-up with system files, and tick previous Windows installations. It usually recovers a large amount at once, and ends your ability to roll back.
Deleted files but space did not change
Cause: Recycle bin not emptied, or the files were in a cloud folder and only removed locally — Fix: Empty the bin. For cloud folders, check whether the service holds them in its own deleted-items area, which may count against the cloud quota rather than the drive.
A folder reports a huge size and looks empty
Cause: Hidden files, or an application data folder — Fix: Show hidden items, and use a disk usage visualiser rather than the file browser. Application data folders are hidden by design and are frequently the answer.
Free space keeps shrinking on its own
Cause: Logs, caches, a runaway application writing continuously, or snapshots accumulating — Fix: Use a visualiser twice, a day apart, and compare. The folder that grew is the culprit, and it is usually a log or a cache belonging to one program.
Questions people ask
How much free space should I leave?
Ten per cent or so, and at least enough for a system update, which can need many gigabytes of working room. A drive run at the very edge of full is slower and more prone to problems.
Is it safe to delete files in a Windows folder or Library folder?
Not by hand. Use the system's clean-up tools, which remove the same things safely and know what is still needed. Manual deletion in system folders is a reliable way to break something.
Why is my 1 TB drive only 931 GB?
Drives are sold in decimal terabytes and reported in binary by the computer. Nothing is missing and there is nothing to reclaim.