Common reasons your Mac slows down
A slow Mac usually comes from one of four things: too many programs running at once, a full hard drive, outdated software, or a hardware problem that needs repair. Most of the time it is the first two. When your Mac feels sluggish, opening a new browser tab takes five seconds, or switching between programs lags, the culprit is almost always memory pressure or storage space running out.
Memory pressure happens when your Mac is trying to run more programs than it has RAM to handle. Your Mac then uses your hard drive as temporary memory, which is much slower. Storage space matters because your Mac needs room to write temporary files while it works. When your drive is nearly full, even straightforward tasks slow down.
Key Takeaways
- Check Activity Monitor to see which programs are using the most memory and CPU power, then close the ones you do not need running.
- Delete large files, old downloads, and duplicate photos to free up hard drive space — your Mac needs at least 10 to 15 percent of your drive empty to run smoothly.
- Restart your Mac regularly, especially after installing updates, because background processes can accumulate and slow performance over time.
- Update macOS and your applications to the latest versions, as updates often include speed improvements and fixes for problems that drain resources.
- If your Mac is still slow after these steps, the hard drive itself may be failing or your Mac may need more RAM than it currently has.
How to check what is using your Mac's memory
Open Activity Monitor, which is in your Applications folder under Utilities. Click the Memory tab at the top. You will see a list of every program running on your Mac and how much memory each one is using. Look for programs you do not recognize or ones that are using a very large percentage — anything over 50 percent is worth investigating.
The programs that use the most memory are usually your web browser, email client, and any video or photo editing software. If you have ten browser tabs open, your browser alone might be using 4 or 5 gigabytes of RAM. Close the tabs or programs you are not actively using. If a program is frozen or not responding, select it and click the X button labeled "Force Quit" at the top of the Activity Monitor window.
After you close programs, check the Memory pressure graph at the bottom of the Activity Monitor window. If it is green or yellow, your Mac has enough memory for what you are doing. If it turns red, your Mac is running out of memory and you need to close more programs or add more RAM.
Free up hard drive space
Your Mac slows down noticeably when your hard drive is more than 85 percent full. To check how much space you have, click the Apple menu in the top left corner, select "About This Mac," and click the Storage tab. You will see a colored bar showing how much space is used and how much is free.
If you have less than 50 gigabytes free, start deleting files. The easiest places to look are your Downloads folder, which often fills with old installers and files you no longer need, and your Trash bin — empty it by right-clicking the Trash icon in your dock and selecting "Empty Trash." Next, look for duplicate photos in your Photos app or old video files in your Movies folder. You can also move large files like old projects or backups to an external hard drive.
If you are not sure what to delete, use a tool like Disk Diag or CleanMyMac to see which folders are taking up the most space. These tools show you a visual map of your hard drive so you can spot large files or folders you forgot about. Be careful not to delete anything in your System or Library folders — stick to your Downloads, Documents, Movies, and Photos folders.
Restart your Mac and check for software updates
Restarting your Mac clears out temporary files and stops background processes that may have been running for weeks. Many users leave their Mac on for months without restarting, and this causes slowdowns over time. Restart at least once a week, or more often if you notice your Mac getting slower as the day goes on.
After you restart, check for software updates. Click the Apple menu, select "System Settings," and click General on the left side. Then click "Software Update." If updates are available, install them right away. macOS updates often include speed improvements and fixes for problems that drain your battery or slow your Mac down. process updates matter too — open the App Store, click Updates at the bottom, and install any updates listed there.
Close browser extensions and background apps
Browser extensions can slow down your web browser significantly, especially if you have more than five or six installed. Open your browser settings, find the Extensions or Add-ons section, and disable any extensions you do not use regularly. Keep only the ones you actually need.
Background app refresh is another common culprit. This feature lets applications update their content even when you are not using them. Go to System Settings, click General, and then click "Login Items." Remove any programs listed under "Allow in the Login Window" or "Open at Login" that you do not need to start automatically. The fewer programs that launch when your Mac starts up, the faster your Mac will boot and run.
Check for malware and viruses
Malware and viruses can slow your Mac down by running hidden processes in the background. While Macs are less commonly targeted than Windows computers, they are not immune. If your Mac is slow and you have tried the steps above, run a malware scan using a tool like Malwarebytes or Avast. These tools are free to read and will scan your Mac for threats.
Be cautious of pop-ups claiming your Mac has a virus — these are usually scams designed to trick you into downloading malware. If you see a suspicious pop-up, close it when ready by pressing Command+Q or closing the browser tab. Do not click on any buttons in the pop-up.
When your Mac needs hardware repair or an upgrade
If you have freed up hard drive space, closed unnecessary programs, restarted your Mac, and updated your software but it is still slow, the problem may be hardware. Your hard drive could be failing, or your Mac may not have enough RAM for the work you are doing.
Hard drives fail gradually — you might notice your Mac freezing for a few seconds at a time, taking a long time to open files, or making clicking or grinding sounds. If you hear unusual sounds from your Mac, back up your files when ready and take it to an Apple Store or a certified repair shop. A failing hard drive can be replaced, usually for $200 to $500 depending on the model.
If your Mac is several years old and you regularly use memory-intensive programs like video editing software or run many browser tabs at once, adding more RAM can make a significant difference. Check how much RAM your Mac currently has by going to Apple menu > About This Mac > Memory. If it has 8 gigabytes or less and you do a lot of multitasking, upgrading to 16 or 32 gigabytes can speed things up noticeably. RAM upgrades cost $100 to $400 depending on your Mac model.
Frequently Asked Questions
Why is my Mac slow only when I use certain programs?
That program is using more memory or CPU power than your Mac can handle smoothly. Open Activity Monitor, click the CPU tab, and run that program. You will see how much CPU it is using. If it is above 80 percent, the program itself may be poorly designed or may need more powerful hardware than your Mac has.
Does clearing my cache and cookies speed up my Mac?
Clearing your browser cache and cookies frees up a small amount of space and can sometimes fix a slow browser, but it is not usually the main cause of slowness. It is worth trying if your browser is the only slow program, but focus first on closing browser tabs and disabling extensions.
Will upgrading to the latest macOS version speed up my Mac?
Sometimes, but not always. Newer versions of macOS often run better on newer Macs but can actually slow down older ones. If your Mac is more than five years old, check online reviews for your specific model before upgrading. If your Mac is newer, the upgrade usually brings speed improvements.
Is it bad to leave my Mac on all the time?
Leaving your Mac on continuously causes slowdowns over time because background processes accumulate and temporary files build up. Restart your Mac at least once a week to clear these out. Restarting also gives your hard drive a chance to defragment itself, which helps performance.
How much free space should I keep on my Mac?
Keep at least 10 to 15 percent of your hard drive free for your Mac to run smoothly. If your drive is 500 gigabytes, that means keeping at least 50 to 75 gigabytes free. The more free space you have, the faster your Mac will perform, especially when you are working with large files.