Why your Mac slows down and what you can do about it

A Mac that has been running for months or years collects clutter — old files you forgot about, browser caches, duplicate photos, and background processes that launch automatically. None of this requires a specialist to fix. Most slowdowns come from one of four sources: a full hard drive, too many apps running at startup, browser bloat, or a drive that needs its storage optimized. You can address each one yourself in under an hour.

The first step is always to restart your Mac. This clears temporary files from memory and stops runaway processes. If that does not help, move to the fixes below in order — start with the easiest and most common culprits before moving to deeper changes.

Key Takeaways

  • Restart your Mac first; this alone fixes slowness caused by memory leaks and background processes.
  • Check how much free storage you have in System Settings > General > Storage — a full drive slows everything down, and you need at least 10 to 15 percent free space.
  • Remove apps that launch at startup by going to System Settings > General > Login Items and deleting ones you do not use daily.
  • Clear your browser cache and disable extensions in Safari, Chrome, or Firefox, since browser bloat is one of the most common causes of slowness.
  • Use Activity Monitor (Applications > Utilities) to see which apps are using the most CPU and memory, and force-quit anything that is stuck or unnecessary.

Check your available storage space first

A Mac with less than 10 percent free storage space will slow down noticeably because the operating system cannot write temporary files efficiently. Open System Settings, click General in the sidebar, then click Storage. You will see a colored bar showing how much space is used and how much is free.

If you have less than 15 gigabytes free on a typical Mac, you need to delete files. Start with the largest items: old video files, duplicate photos, or downloads you no longer need. Drag them to the Trash, then empty the Trash. If you use iCloud Photos, you can also reduce local storage by going to System Settings > [Your Name] > iCloud > Photos and switching to "Optimize Mac Storage" — this keeps full-resolution photos in iCloud and stores smaller versions locally.

Remove apps that launch when you start your Mac

Every app set to launch at startup uses memory and processor power before you even open it. Open System Settings, click General in the sidebar, then click Login Items. You will see a list of apps that start automatically. Remove any you do not use every single day by selecting them and clicking the minus button.

Pay special attention to cloud storage apps (Dropbox, OneDrive, Google Drive), messaging apps, and communication tools — these are often set to launch by default and can consume significant resources in the background. If you use them only occasionally, remove them from startup and open them manually when you need them.

Clear your browser cache and disable unused extensions

Safari, Chrome, and Firefox all accumulate cached data and run extensions that slow down browsing and sometimes the entire system. In Safari, go to History > Clear History, set the time range to "All History," and click Clear History. In Chrome, go to Settings > Privacy and Security > Clear Browsing Data, select "All Time," and click Clear Data.

Next, disable browser extensions you do not actively use. In Safari, go to Settings > Extensions and uncheck anything you rarely need. In Chrome, go to Settings > Extensions and remove or disable extensions. Each extension runs code in the background and can slow your browser significantly. Keep only the ones you use regularly.

Use Activity Monitor to find resource hogs

Activity Monitor shows you exactly which apps are using the most CPU (processor) and memory (RAM). Open Applications > Utilities > Activity Monitor. Click the CPU tab to see which apps are using processor power right now. If you see an app using 50 percent or more of CPU when you are not actively using it, that is a problem.

Click on the app and then click the X button (Force Quit) to stop it. If the same app keeps appearing, it may have a bug or may be set to run in the background. You can then decide whether to uninstall it, update it, or remove it from your startup items. Check the Memory tab as well — if a single app is using more than 2 to 3 gigabytes of RAM, it is consuming more than it should.

Update macOS and your apps

Older versions of macOS and apps often run less efficiently than newer ones. Go to System Settings > General > Software Update and install any available updates. This usually takes 10 to 30 minutes and often includes performance improvements.

Update your apps as well. Open the App Store, click Updates in the toolbar, and install any pending updates. If you use apps outside the App Store, check their individual websites or built-in update features. Outdated apps sometimes consume more resources than they should.

Reduce visual effects if your Mac is still slow

macOS includes animations and visual effects that look polished but consume processor power. If your Mac is still slow after the steps above, you can disable some of these. Go to System Settings > Accessibility > Display and toggle on "Reduce motion" and "Reduce transparency." These changes are subtle but can help on older Macs or those with less powerful processors.

You can also disable some background app refresh. Go to System Settings > General > Background App Refresh and uncheck apps you do not need to update in the background. Mail, Messages, and calendar apps often refresh constantly — if you check them manually instead, disabling background refresh can help.

When to take your Mac to a professional

If your Mac is still slow after you have restarted it, freed up storage, removed startup apps, and cleared your browser, the problem may be hardware-related. A failing hard drive, failing battery, or overheating can all cause slowness. You can check your drive health by opening Disk Utility (Applications > Utilities > Disk Utility), selecting your drive, and clicking First Aid. If it reports errors, your drive may be failing and you should have it checked by an Apple Store or certified technician.

If your Mac is more than five years old and still slow after these steps, it may straightforward be reaching the end of its useful life for your needs. Upgrading RAM or replacing the drive with a solid-state drive (SSD) can help, but that requires professional installation on most Macs.

Frequently Asked Questions

How much free storage space do I actually need?

You need at least 10 to 15 percent of your total drive capacity free for macOS to run efficiently. On a 256 GB drive, that means 25 to 40 GB free. On a 512 GB drive, 50 to 75 GB free. If you are below that, your Mac will slow down noticeably.

Is it safe to force-quit apps in Activity Monitor?

Yes, force-quitting an app in Activity Monitor is safe. You may lose unsaved work in that app, but it will not damage your Mac or other apps. If an app is frozen or using excessive resources, force-quitting it is the right move.

Will disabling startup apps make my Mac slower to start?

No — disabling startup apps makes your Mac faster to start. Fewer apps launching at startup means faster boot times and less memory used when you first turn on your Mac. You can always open apps manually when you need them.

What is the difference between restarting and shutting down?

Restarting closes all apps and clears memory, then starts fresh. Shutting down does the same but also powers off the Mac completely. Both clear temporary files and stop runaway processes. Restarting is usually faster if you plan to use your Mac again soon.

Can I speed up my Mac without buying new hardware?

Yes — the steps in this guide address the most common causes of slowness and require no hardware changes. If your Mac is still slow after you have done all of them, hardware upgrades (more RAM, a faster drive) may help, but most slowness comes from software clutter, not hardware limits.