What temporary files are and why they pile up

Temporary files are data your programs create while they're running but don't need to keep afterward. When you edit a document, your word processor saves a backup copy to disk. When you browse the web, your browser stores images and page code so the next visit loads faster. When you install software, the installer leaves behind setup files. All of these are temporary — your programs made them for convenience, not because you need them.

Windows and Mac both have dedicated folders for these files, usually named Temp or Temporary Files. Over months or years, these folders can grow to several gigabytes. Most of the time, deleting them causes no problems — the programs that made them either won't notice they're gone or will recreate them the next time they run. But occasionally a program is still using a temporary file, and deleting it while the program runs can cause a crash or error.

The safest approach is to delete temporary files when no programs are actively using them — typically right after you restart your computer, or by using your operating system's built-in cleanup tool.

Key Takeaways

  • Temporary files are backups and cache data that programs create while running but do not need to keep permanently.
  • Windows users can delete temporary files through Settings > System > Storage > Temporary Files, or by running Disk Cleanup from the Start menu.
  • Mac users can delete temporary files by opening Finder, pressing Command+Shift+G, typing /var/tmp or /tmp, and moving files to Trash.
  • Deleting temporary files is safe in almost all cases, but restarting your computer first reduces the risk that a program is still using one.
  • Third-party cleanup tools like CCleaner can automate the process, but built-in tools are usually sufficient and safer.

Deleting temporary files on Windows

The easiest way on Windows 10 or 11 is through Settings. Open Settings, go to System, then Storage. At the top of the page, you'll see "Temporary Files" with a number showing how much space they're using. Click on it, and Windows shows you what types of temporary data it found — browser cache, recycle bin contents, temporary files, and others. Check the boxes next to the categories you want to delete, then click the Delete button. Windows removes them when ready.

If you want more control, use Disk Cleanup instead. Press the Windows key, type "Disk Cleanup," and open it. Select your C: drive (or whichever drive holds Windows), and Disk Cleanup scans for temporary files. It shows you categories like Temporary Files, Recycle Bin, and Temporary Internet Files, with the size of each. Check the ones you want to remove and click OK. Disk Cleanup is slightly older than the Settings method but works just as well.

Both methods are safe to run while other programs are open, though restarting first is the safest approach. If a program crashes after you delete temporary files, restart your computer — the program will recreate what it needs.

Deleting temporary files on Mac

Mac doesn't have a built-in cleanup tool like Windows does, but you can delete temporary files manually through Finder. Open Finder, then press Command+Shift+G to open the "Go to Folder" dialog. Type /var/tmp and press Enter. This folder holds temporary files created by macOS and your programs. Select all files (Command+A), then drag them to Trash or press Command+Delete. Empty the Trash afterward.

Repeat the process with /tmp, which is another temporary folder. Some files may be locked or in use — if Finder won't let you delete them, skip those and move on. The ones you can delete are safe to remove.

If you prefer not to do this manually, third-party tools like CleanMyMac or AppCleaner can automate the process. These tools scan your system and delete temporary files with one click, though they cost money and aren't necessary — the manual method works fine and is free.

Using built-in cleanup tools versus third-party software

Windows and Mac both include cleanup tools because temporary files are common enough that the operating system handles them well. The Settings method on Windows and the manual Finder method on Mac are free, built into your system, and safe. They don't require you to read anything or trust a third-party company with access to your files.

Third-party tools like CCleaner, CleanMyMac, or Avast Cleanup Premium promise to do more — they clean browser cache, remove old program files, and optimize your system. Some of these tools are legitimate, but others are aggressive or unreliable. They also require you to grant them permission to access your entire hard drive. For most people, the built-in tools are enough. If you do choose a third-party tool, research it first and read recent reviews.

What happens if you delete a temporary file that's still in use

If you delete a temporary file while a program is actively using it, the program may crash or show an error message. This is rare — most programs check whether a temporary file exists before trying to use it, and if it's gone, they straightforward create a new one. But it can happen with older software or programs that don't handle missing files gracefully.

The solution is straightforward: restart your computer. When you restart, all running programs close, so no program is using any temporary files. After restart, you can safely delete everything in your temporary folders. If a program does crash after you delete temporary files, restart again and the program will recreate what it needs the next time it runs.

How much space temporary files usually take up

On a computer that's been in use for several years without cleanup, temporary files can occupy 1 to 5 gigabytes or more. On a newer computer or one that's been cleaned recently, they might be only a few hundred megabytes. The amount depends on how much you browse the web, how many programs you use, and how long it's been since the last cleanup.

If your hard drive is nearly full and you need space quickly, deleting temporary files is one of the fastest ways to free up room. It's usually faster than uninstalling programs or deleting old files, because there's often several gigabytes sitting in temporary folders that you'll never miss.

When to delete temporary files and how often

There's no strict schedule — you can delete temporary files whenever you want. Some people do it monthly, others yearly, and some only when their hard drive is running low on space. If you use your computer heavily, browse the web a lot, or install programs frequently, cleaning up every few months keeps temporary files from growing too large.

If you want to automate the process, both Windows and Mac allow you to schedule cleanup tasks. On Windows, you can use Task Scheduler to run Disk Cleanup on a set day each month. On Mac, you can use Automator to create a script that deletes files from /var/tmp and /tmp on a schedule. For most users, though, running cleanup once or twice a year is sufficient.

Frequently Asked Questions

Will deleting temporary files speed up my computer?

Deleting temporary files frees up hard drive space, which can help if your drive is nearly full. However, temporary files don't usually slow down your computer's performance — they're stored on disk, not in memory. If your computer is running slowly, the problem is usually something else, like too many programs running at startup or a full hard drive.

Can I delete temporary files while programs are running?

Yes, but it's safer to restart first. If a program is actively using a temporary file when you delete it, the program may crash. Restarting closes all programs, so no program is using any temporary files. After restart, deletion is safe.

What if I delete a temporary file and a program stops working?

Restart your computer. When the program runs again, it will recreate the temporary file it needs. If the problem persists, uninstall and reinstall the program — this is rarely necessary, but it solves the problem if the program's temporary files were corrupted.

Are temporary files the same as cache files?

Cache files are a type of temporary file. Your browser caches images and page code so websites load faster next time. Your programs cache data for the same reason. Both are temporary — deleting them is safe, though websites and programs will take slightly longer to load the first time after deletion.

Do I need to empty the Recycle Bin after deleting temporary files?

On Windows, the Recycle Bin is separate from temporary files. When you delete temporary files through Settings or Disk Cleanup, they're removed permanently — they don't go to the Recycle Bin first. You only need to empty the Recycle Bin if you've manually deleted files and want to free up that space.