Why is my Mac freezing and running slow?

If your Mac is freezing, lagging, or running slower than usual, it can be incredibly frustrating. A sluggish Mac can make simple tasks take much longer and sap your productivity. Fortunately, there are a number of troubleshooting steps you can try to get your Mac back up to speed.

Quick Fixes to Try First

Before diving into more complex solutions, try these quick fixes that may solve a freezing or slow Mac:

  • Restart your Mac – A simple restart can clear out memory issues and refresh processes. Shut down and restart your Mac to see if performance improves.
  • Force quit apps – Apps that are not responding may be bogging your system down. Force quit unresponsive apps by going to the Apple menu > Force Quit.
  • Check for software updates – Make sure your system software, apps, and drivers are all up-to-date by going to the Apple menu > System Preferences > Software Update.
  • Clear browser caches – Large browser caches can slow down web browsing. Clear your Safari, Chrome, or Firefox caches.
  • Check Activity Monitor for resource hogs – Use Activity Monitor to see if any processes are using high CPU or RAM and force quit them.

Check for Malware, Viruses and Other Infections

Sometimes freezes and slow performance are caused by malware that has infected your system. Try scanning your Mac with a reputable anti-virus program to detect and remove any harmful infections.

Some good options include:

  • Malwarebytes – Scans for viruses, malware, spyware and adware.
  • Avast Security – Free real-time protection against ransomware and other threats.
  • Bitdefender Virus Scanner – Fast, free on-demand virus scanning.

Run a full system scan and delete anything harmful that is detected. After removing infections, restart your Mac to see if that resolves freezing and sluggish behavior.

Try Safe Mode

Booting into safe mode loads only essential macOS files and services. If your Mac runs well in safe mode, it indicates that another program or startup item is likely causing problems.

To start in safe mode:

  1. Fully shut down your Mac
  2. Restart your Mac and immediately press and hold the Shift key
  3. Let go of Shift once you see the login window (Safe boot will be in the top right corner)
  4. Log in normally and test for freezing or slowness
  5. Restart back into normal macOS after testing

If your Mac works fine in safe mode, it means some third-party application, login item or system configuration is slowing it down. You can troubleshoot from there.

Check for Overheating Issues

Excessive heat can cause a Mac’s CPU and components to throttle down their speeds, resulting in sluggish performance. Use Activity Monitor to watch for high CPU temperatures.

Here are some tips if your Mac is overheating:

  • Clean dust – Dust buildup in heat sinks and fans can cause overheating. Carefully clean out built-up dust from inside your Mac.
  • Check fans – Make sure cooling fans are functional and clear of obstructions.
  • Reapply thermal paste – Reapplying thermal paste between the CPU and heat sink can improve cooling.
  • Adjust workspace – Make sure your Mac has good airflow around it and is not on surfaces like beds or sofas that trap heat.
  • Use a cooling pad – External USB cooling pads with fans can help keep your Mac cool.

Free Up Disk Space

A full or nearly full hard drive can bog down your Mac’s performance. Try to keep at least 10-20% of your startup disk free.

To free up space:

  • Empty Trash Bin
  • Remove unneeded files and apps
  • Store files on external drives
  • Use Optimized Storage in About This Mac to reduce clutter
  • Use Disk Utility’s First Aid to find and delete unused files

Adding more RAM or upgrading to a larger internal hard drive can also help improve limited storage space issues.

Check Login Items

Too many apps and services launching at login can slow down your boot time and opening apps. Review your login items in System Preferences > Users & Groups > Login Items. Remove anything unnecessary.

Resolve Software Conflicts

Incompatible or problematic software can sometimes cause freezes, crashes, and slowdowns. If you recently installed new software or drivers, try uninstalling them as a troubleshooting step.

Also pay attention to any error messages during crashes as they may identify a problematic app. Search online to see if similar problems have been reported with a particular app and if any solutions are available.

Check for Failing Hardware

Faulty hardware like RAM, hard drives, and cables can produce system instability, freezes and sluggishness. Some steps to identify failing hardware:

  • Run Apple Diagnostics – This checks your Mac’s RAM, storage and other components.
  • Test RAM – Use Memory Tester or Rember to check for RAM issues.
  • Check SMART status – Use a tool like DriveDX to check if your hard drive is failing.
  • Try external devices – Remove peripherals and see if problems persist to isolate issues.

If you determine faulty hardware is the culprit, you may need a repair or replacement of those components.

Check Activity Monitor for Resource Hogs

Apps, processes and services using high CPU, memory, disk or network can slow down your Mac. Use Activity Monitor to sort by CPU, Memory or Energy Impact to identify processes you can quit or limit.

Watch for anything suspicious using excessive resources. Google processes you don’t recognize to see if they are legitimate. Force quit or uninstall unneeded processes.

Reset SMC and NVRAM

Resetting your Mac’s System Management Controller (SMC) and Non-Volatile Random Access Memory (NVRAM) can help resolve freezing issues and improve performance in some cases.

To reset SMC on MacBooks and Macs with T2 chips:

  1. Shut down Mac
  2. Press and hold power button for 10 seconds
  3. Release power button and wait a few seconds
  4. Power on Mac as normal

For Macs without T2 chips, the steps are:

  1. Shut down Mac
  2. Unplug power cable
  3. Press and hold power button for 5 seconds
  4. Release power button
  5. Plug power cable back in and start Mac

To reset NVRAM:

  1. Shut down Mac
  2. Power on Mac and immediately press Command + Option + P + R keys
  3. Hold keys until you hear the startup chime a second time
  4. Release keys and let Mac boot normally

Update or Reinstall macOS

An outdated OS or corrupted system files could be causing performance issues. Updating to the latest macOS version can resolve bugs and optimization issues.

If updating does not help, a clean reinstall of macOS may be needed to address underlying system file problems. Back up your data first, then boot to macOS Recovery or your installer drive to reinstall the OS.


With the right troubleshooting steps, you can get to the bottom of what is causing a freezing or slow Mac. Start with simpler steps like restarting, force quitting apps, clearing browser caches and checking for malware. If the problem persists, dig deeper into hardware problems, memory issues, software conflicts and system reinstalls. Monitoring Activity Monitor is key to pinpointing processes and apps bogging down your Mac. With patience and diligence, you will be able to get your Mac back to running smoothly.