Random freezes usually come from one of four sources: your hard drive running out of space, too many programs running at once, overheating, or a driver that needs updating

When your computer freezes, it stops responding to your mouse, keyboard, or trackpad for anywhere from a few seconds to several minutes. The screen may go blank, show a spinning wheel, or just lock in place. Most of the time, the cause is something you can identify and fix yourself without opening the machine or calling for help.

The four most common culprits are a full hard drive (which leaves no room for the operating system to work), too many browser tabs or programs running simultaneously, a processor that has overheated and throttled itself down, or an outdated driver for a piece of hardware like your graphics card or network adapter. Less often, a failing hard drive or a virus can cause freezes, but these are less common than the four above.

Key Takeaways

  • Check how much free space is on your hard drive—if it is below 10 percent of total capacity, your computer will slow down and freeze.
  • Open your Task Manager (Windows) or Activity Monitor (Mac) to see which programs are using the most memory and processor power, then close the ones you do not need.
  • Make sure your computer's vents are clear of dust and the fan is running; overheating is a common cause of freezes that feels like a software problem.
  • Update your drivers through Device Manager (Windows) or System Preferences (Mac), especially for your graphics card and network adapter.
  • If freezes happen only when you do one specific task—like opening a certain program or visiting a website—that task is the source, not your whole system.

Check your hard drive space first

Your operating system needs free space on your hard drive to create temporary files, cache data, and run programs. When your drive is more than 90 percent full, your computer has almost no room to work and will freeze frequently.

On Windows, right-click the C: drive in File Explorer and select Properties. You will see a pie chart showing used and free space. On Mac, click the Apple menu, select About This Mac, then click Storage. If your free space is less than 10 percent of your total drive size, you need to delete files or move them to an external drive. Start by emptying your Downloads folder and your Recycle Bin (Windows) or Trash (Mac), then look for large video or photo files you no longer need.

If you are close to full but not quite there, clearing your browser cache can free up several gigabytes. In Chrome, Firefox, or Edge, press Ctrl+Shift+Delete (Windows) or Command+Shift+Delete (Mac), select "all time," and click Clear Data.

Close programs that are using too much memory

Every open program, browser tab, and background service uses a portion of your computer's memory and processor power. When too many things run at once, your system runs out of resources and freezes while it tries to decide what to do next.

On Windows, press Ctrl+Shift+Esc to open Task Manager. Look at the Memory and CPU columns—the programs at the top are using the most resources. If you see something you do not recognize or do not need right now, click it and select End Task. On Mac, press Command+Space, type Activity Monitor, and press Enter. Click the Memory or CPU tab to sort by usage, then select a program and click the X button to close it.

Browser tabs are often the biggest culprit. If you have 20 or 30 tabs open, close the ones you are not actively using. Video streaming, online games, and cloud storage services running in the background can also drain resources—check your startup programs and disable the ones you do not need to run automatically when your computer starts.

Make sure your computer is not overheating

When your processor gets too hot, it automatically slows itself down to cool off. This slowdown feels like a freeze because your computer becomes unresponsive for 10 to 30 seconds at a time. If this happens regularly, overheating is likely the cause.

Listen for your fan. If it is running constantly and loudly, your computer is working hard to cool itself. Check the vents on the sides, back, and bottom of your laptop or desktop—if they are clogged with dust, air cannot flow through and heat builds up. Use a can of compressed air to blow dust out of the vents, holding the can upright and using short bursts. Do this outside or in a well-ventilated area, as a lot of dust will come out.

If your laptop is on a soft surface like a bed or couch, move it to a hard, flat surface like a desk. Soft surfaces block the vents underneath. You can also buy a laptop cooling pad with a built-in fan for about $20 to $40, which sits under your laptop and pulls heat away. If your desktop computer is in a hot room or enclosed space, moving it to a cooler location or improving airflow around it can help.

Update your drivers

A driver is software that lets your operating system talk to a piece of hardware—your graphics card, network adapter, sound card, or touchpad. When a driver is outdated or corrupted, it can cause freezes, especially when you use that hardware.

On Windows, right-click the Start button and select Device Manager. Look for any devices with a yellow exclamation mark—these have a problem. Right-click the device and select Update Driver, then choose Search automatically for updated driver software. Windows will read and install the latest version from the manufacturer. Pay special attention to your graphics card (listed under Display adapters) and your network adapter (under Network adapters).

On Mac, click the Apple menu, select System Settings, then click General and Software Update. Mac will check for updates to your operating system and drivers automatically. If you have an older Mac, you may need to visit the manufacturer's website for your graphics card or other hardware to read drivers manually.

Identify if one task is causing the freeze

Pay attention to when your computer freezes. If it happens only when you open a specific program, visit a certain website, or perform one particular task, that task is the problem, not your whole system.

If a program freezes your computer every time you use it, try uninstalling and reinstalling it. On Windows, go to Settings, Apps, Apps & Features, find the program, and click Uninstall. On Mac, open Applications, drag the program to Trash, and empty Trash. Then read the latest version from the manufacturer's website and install it fresh.

If a website freezes your browser, try disabling browser extensions. In Chrome, click the three-dot menu, select Extensions, and toggle off extensions one at a time until the freezing stops. The extension you disabled is the culprit. In Firefox, click the menu button, select Add-ons, and disable extensions the same way.

When to restart your computer or seek help

If you have tried the steps above and your computer still freezes randomly, restart it. Many temporary problems clear themselves after a restart. On Windows, click the Start button and select Restart. On Mac, click the Apple menu and select Restart.

If freezes continue after a restart and you have ruled out the four main causes above, your hard drive may be failing or your computer may have a virus. A failing hard drive will often freeze, make clicking or beeping sounds, or show a message that files cannot be found. A virus or malware can cause freezes along with other strange behavior. At this point, back up your important files to an external drive or cloud storage, then take your computer to a repair shop or contact the manufacturer's support line. Do not ignore repeated freezes—a failing hard drive can lose data if it fails completely.

Frequently Asked Questions

Why does my computer freeze but not crash?

A freeze is your computer still running but unable to respond to your input. A crash is when the program or operating system stops working entirely. Freezes usually mean your system is overloaded or waiting for a slow operation to finish. Crashes usually mean a program has a bug or your hardware is failing.

Can a virus cause random freezes?

Yes, but it is less common than the four main causes. A virus or malware can use your processor and memory in the background, causing freezes. If you suspect a virus, run a full scan with Windows Defender (Windows) or Malwarebytes (both Windows and Mac). If a scan finds nothing and freezes continue, the cause is probably overheating, a full drive, or too many programs running.

Does restarting my computer actually fix freezes?

Restarting clears your computer's memory and stops all running programs, which fixes many temporary freezes. However, if the underlying cause is a full hard drive, overheating, or an outdated driver, the freezes will return after a restart. Restart as a first step, but if freezes come back, work through the other causes.

Is it safe to force-quit a frozen program?

Yes. On Windows, press Ctrl+Shift+Esc, find the frozen program, and click End Task. On Mac, press Command+Option+Esc, select the program, and click Force Quit. You may lose unsaved work in that program, but force-quitting will not damage your computer or other programs.

Why does my computer freeze only when I play games?

Games use your graphics card and processor heavily. If your computer freezes only during games, the cause is usually overheating, an outdated graphics driver, or insufficient free hard drive space. Update your graphics driver first, then check your hard drive space and make sure your vents are clean.