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Updated: 21 Apr 2022

How to free up disk space

Hard drive full? Read our quick and easy solutions to help free up some disk space on your PC.
Which?Editorial team

A full hard drive isn't just an inconvenience; it can have a serious impact on the speed and even security of your computer. 

Fortunately there are some easy ways to delete unnecessary files from your hard drive, and make sure you don't run into this problem again.

Whatever your budget, our lab tests reveal which models are worth your money and which aren't. See our expert pick of the best laptops for 2022.

Problems caused by a full hard drive

Don’t wait until your hard drive is completely full before cleaning it out; you’ll start to run into problems well before it’s bursting at the seams. Here are some common issues that could be caused by a lack of space.

  • Unable to download files: new software or important updates may not have enough space to download or install.
  • Errors and restarts: computer updates can fail, or cause your computer to restart constantly as it tries again.
  • General slowdown: your PC may appear to be running slowly for no obvious reason, as it struggles to find room to manage your day-to-day tasks.
  • File and application slowdown: files and apps could be taking longer to open because there is so little space to store the temporary files they need to run smoothly.
  • Interruptions: pop-up messages may appear from programs that can no longer function properly.

Quick disk space-saving tips

The first thing you should check is whether there are any quick fixes that can get you some free space right away. 

  1. Empty the recycle bin, desktop and your downloads folder of stuff you don’t need.
  2. Use Windows storage settings and Storage Sense to set up rules on how your PC will deal with files you don’t need.
  3. Uninstall. Go through the programs installed on your computer (search ‘add or remove programs in the start menu’) to see if there’s any old software you don’t need.
  4. Back up files you don’t use frequently –  including documents and photos – to a cloud service or USB drive, then delete them from your computer, safe in the knowledge that they're now stored elsewhere.

Having more problems than just storage? See our guide on how to speed up a slow computer.

What to do if Windows needs more space to update

If you've tried all of the above but still don't have enough space, it's time to look at some more advanced solutions.

This is an incredibly common problem that people with very cheap computers often run into because their laptop had very little storage to begin with.

The simple solution is to connect either an SD, micro-SD or USB storage drive (also known as a pen drive or USB stick), but Windows will still make you jump through some extra hoops before it lets you do this. The message that pops up to say ‘Windows needs more space’ will require you to free up space using the Storage Sense tool to claw back at least 4GB of storage. If this is proving difficult, read the next few sections of this article to see how else you can save more space.

Once you've found that magic 4GB, Windows should let you pick a drive or SD card that you’ve plugged in, and allow you to continue your update. On computers with only 16GB or 32GB of storage, it’s sensible to always have a micro-SD card plugged in so that this problem is less likely to occur in the future.

Use Windows tools to free up disk space

A great place to start freeing up space is by using the Storage Sense tool that’s pre-installed on the more recent versions of Windows 10. If you don’t have Storage Sense yet, you may need to update your computer to the latest version. Open the Start menu, type Storage into the search box and click on Storage settings. Under the option ‘free up space now’, you’ll find out how much space problematic and hidden files are taking up. You can then take action and delete the files that are causing you problems. Beware, though, these files will be deleted permanently; there will be no second chances.

How to find large files that are taking up space

If you know there are certain folders that might contain large files, such as the documents or downloads folder, navigate to them using File Explorer, click View and then Details. You can then sort files by size by clicking on the Size column. Also look out for a file called ‘Windows.old’. This file can be huge, and is a by-product of upgrading a computer to Windows 10 from a previous version. It’s largely useless, and can safely be deleted

And, of course, don’t forget to empty the recycle bin on occasion. You can set this to happen automatically using Storage Sense.

You you can search for large files, even if you don't know where they are. Open an Explorer window and click the Search box at the top right. You should now see a Search Tools menu bar appear. Click the Size dropdown and choose Huge or Gigantic to view the main offenders. Hit Enter afterwards and your PC will run a search for large files in every folder. 

If you need more help, TreeSize Free from JAM Software (see below) lets you see specifically which files and folders on your computer are taking up the most space. A word of caution, though: there are certain files you don’t want to delete under any circumstances. For instance, things inside the Windows folder should be treated as essential, as should files relating to software you use regularly.

Things you should never do to free up disk space

Desperate times, desperate measures? Perhaps, but there are some lines you shouldn't cross, and doing so could end up causing more problems in the future.

1. Don’t use free 'PC cleaning tools', no matter how much they're claimed to be able to achieve. Many of these programs actually do what they claim, but they’ll delete files indiscriminately, and some even end up deleting crucial system files that keep your computer and its programs running smoothly. What’s more, many free options can contain malware and pop-up advertising, and might even force you to upgrade to a premium version for a huge sum of money. Steer clear.

2. Don’t clean up the registry. People who are comfortable with computers know that messing around with the Windows 10 registry – the place where crucial configuration files are stored – is a last resort. It can be a handy way to save some space, but the damage that can be done from deleting or modifying the wrong registry files far outweighs the potential space savings.

3. Don't delete critical system folders from the C drive including program files, System32, Windows and Pagefile.sys. It might be tempting since these files are huge, but your computer won’t work properly (or at all) without them.

4. Don't delete or empty storage devices you don't recognise, such as the D drive when you're convinced your computer only came with one drive to begin with. This normally means you have what’s called a backup partition. This is a place that Windows can recover itself from. It’s particularly useful on laptops because it contains all the tools and drivers required to have your computer up and running if you ever need to reset it. We wouldn’t ever recommend attempting to delete this partition.

If all else fails...

Reset your computer by searching for ‘reset’ in the Start menu and clearing everything in one fell swoop. This will also help your PC to feel faster, too. Just make sure you’ve backed up everything you need.

How much storage space do I need on a laptop?

If you've run into these sorts of problems before, chances are you've decided that the next time you upgrade your laptop, you'll make sure you buy one with enough space. 

The bigger the internal storage space on a laptop the better, but it can add a significant amount to the upfront cost, which isn't ideal if you're on a tight budget. Also, getting lots of space might mean you end up saddled with a slower hard disk where an solid-state drive (SSD) would have been preferable. Our guide to SSDs vs hard disks explains more.

While Microsoft has set Windows 10's minimum storage requirement at 32GB, we'd recommend a minimum of 64GB of storage on any new Windows laptop, which can then be comfortably expanded with a microSD card fairly cheaply. Of course, it's not always possible to extend your budget, so buying a 32GB laptop and adding a micro-SD card is also a valid option.

Want a laptop with more storage? Click here to see all laptops with at least 64GB of storage space