How to fix Mac that is running very slow or has poor performance

Summary

This guide helps you troubleshoot and resolve: How to fix Mac that is running very slow or has poor performance. Follow the steps below to fix the issue.

Common Causes

If your Mac has started feeling sluggish, taking ages to start up, or struggling to run multiple apps at once, there are several reliable steps you can take to diagnose and resolve the issue. This guide walks you through the most common causes of poor performance on macOS and how to address them, from quick wins through to deeper troubleshooting.

Quick Fix Steps

Before diving into detailed diagnostics, try these fast solutions that resolve most performance issues:

1. Restart your Mac — Choose Apple menu > Restart. A fresh boot clears temporary memory and resets running processes.
2. Check for macOS updates — Go to System Settings > General > Software Update and install any pending updates.
3. Free up disk space — Ensure you have at least 10–15% of your startup disk free. Go to System Settings > General > Storage to review what's taking up space.
4. Quit unused apps — Close any applications you're not actively using, especially those with large memory footprints.

Detailed Instructions

Check Activity Monitor for Resource Hogs

Activity Monitor is macOS's built-in performance dashboard. It shows you exactly what's consuming your CPU, memory, energy, and disk resources.

1. Open Activity Monitor from Applications > Utilities, or press Cmd + Space and type "Activity Monitor".
2. Click the CPU tab. Look for any process using a high percentage of CPU when you're not actively using it. Sort by the % CPU column.
3. Click the Memory tab. The Memory Pressure graph at the bottom should be mostly green. If it's red, your Mac is running low on RAM.
4. Click the Energy tab. Look for apps with a high Energy Impact score, as these drain battery and slow performance.
5. Click the Disk tab. Check for any process reading or writing large amounts of data.
6. If you find an unresponsive or resource-heavy app, select it and click the X button in the toolbar to quit it.

Manage Startup Items

Too many apps launching at login is one of the leading causes of slow startup and sluggish performance.

1. Open System Settings > General > Login Items.
2. Review the list under Open at Login. Select any items you don't need to launch automatically.
3. Click the minus (–) button to remove them.
4. Also check the Allow in the Background section and disable any apps that don't need to run in the background.

Clear System and User Caches

Over time, cached files can accumulate and slow your Mac down. Clearing them can help, though macOS will rebuild necessary caches automatically.

1. Open Finder and choose Go > Go to Folder from the menu bar, or press Shift + Cmd + G.
2. Enter ~/Library/Caches and press Return.
3. Move the contents of this folder to the Trash (don't delete the folder itself). You may need to enter your administrator password.
4. Repeat for /Library/Caches (the system-wide cache folder).
5. Empty the Trash and restart your Mac.

Free Up Disk Space

macOS uses available disk space as virtual memory. When your disk is nearly full, performance suffers significantly.

1. Open System Settings > General > Storage.
2. Wait for the storage breakdown to load, then review each category (Applications, Documents, Mail, etc.).
3. Click Recommendations for one-click options like Store in iCloud, Optimise Storage, and Empty Trash Automatically.
4. Manually review and delete large files you no longer need from Documents, Downloads, and Movies.
5. Uninstall unused applications by dragging them from Applications to the Trash, then use a tool like App Cleaner to remove leftover files, or right-click an app in Applications and choose Move to Trash.

Reset NVRAM/PRAM and SMC

Resetting these can resolve certain performance and hardware-related glitches, particularly on Intel-based Macs.

For Apple Silicon Macs (M1, M2, M3, M4):

1. Shut down your Mac completely.
2. Press and hold the power button for at least 10 seconds.
3. Release the button, then start your Mac normally. NVRAM/SMC reset happens automatically.

For Intel-based Macs:

1. Shut down your Mac.
2. Press the power button, then immediately hold Option + Cmd + P + R for about 20 seconds.
3. Release the keys when the Apple logo appears and disappears a second time, or when you see the login screen.

Troubleshooting

Check for Malware

Although macOS is generally secure, adware and unwanted software can still slow your Mac considerably.

1. Open System Settings > Privacy & Security > Profiles. If you see any configuration profiles you didn't install, remove them.
2. Open System Settings > Privacy & Security > Extensions and review installed extensions. Disable any you don't recognise or no longer need.
3. Download and run Malwarebytes for Mac (free version) from the official website to scan for and remove adware or malware.
4. Review your Applications folder and uninstall anything you didn't intentionally install.

Test in Safe Mode

Safe Mode starts macOS with only essential components, which helps identify whether third-party software is causing the slowdown.

1. Shut down your Mac.
2. For Intel Macs: Turn on your Mac and immediately hold the Shift key until the login window appears.
3. For Apple Silicon Macs: Press and hold the power button until startup options appear, then hold Shift while clicking Continue in Safe Mode.
4. Log in and test performance. If your Mac runs smoothly in Safe Mode, a third-party app or login item is likely the cause.
5. Restart normally to exit Safe Mode.

Consider Hardware Limitations

If your Mac is several years old, it may simply be struggling with the demands of modern macOS and applications. Signs include:

• Constant fan noise and heat
• Spinning beachball or rainbow cursor appearing frequently
• Apps crashing or refusing to open
• Very long startup times even after troubleshooting

If this sounds familiar, check your Mac's specifications via Apple menu > About This Mac. Older Macs with limited RAM or storage may benefit from an upgrade, but if your model is no longer supported by the latest macOS versions, it may be time to consider a replacement.

For ongoing performance issues that aren't resolved by the steps above, consider booking an appointment with an Apple Authorised Service Provider or contacting Apple Support directly for a hardware diagnostic.

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