Filed Under: How to Repair, Mac

How to Fix the macOS Big Sur Running Slow Issue Easily


Written by Jack Lin

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macOS Big Sur Running Slow

Are you facing the macOS Big Sur slow problem on your Mac? Recently, Apple launched a new macOS version known as Big Sur.

This macOS comes with various amazing features and enhancements within the application. Usually, new updates have a tendency to crash, have bugs, take up more space, slow down, or even affect the device’s performance.

So, in case you have recently updated the macOS, and your Mac is running pretty slow, read further.

Here, you will find different ways to fix the macOS Big Sur Running slow issue.

Why Is Your macOS Big Sur Running Slow?

Every new OS update comes with extra features for the Mac. So that’s why it needs more storage space, resources, and memory on your iOS device than in earlier operating systems. This new upgrade is designed especially for modern Mac device models that are efficient and capable.

So, these updates make the previous Mac version function slower than normal. These OS updates make the system run sluggishly after the Big Sur macOS update.

Before you update your Mac, ensure that your system supports the recent update and is compatible first. The new update supports devices later than MacBook 2015, MacBook Air 2013, Mac mini 2014, MacBook Pro Late 2013, iMac 2014, iMac Pro 2013, iMac 2014, or iMac Pro 2017.

PS: let’s learn more about how to defrag Mac.

How to Resolve the macOS Big Sur Running Slow Issue After Updating to macOS Big Sur?

If your macOS is running slowly after updating to Big Sur, fix it in the following ways.

1. Employ a Mac Optimizing Tool

Is your macOS Big Sur running slow? If so, there is no need to install the earlier macOS version. The most effective and quickest way to resolve the macOS Big Sur slow issue is to use a Mac optimization tool.

We recommend you use CleanMyMac to speed up your Mac. This software helps in preventing macOS Big Sur from running slowly using effective means. Here are some reasons why this application should use:

  • Speed up Mac effectively: Mac runs faster twice than before you use CleanMyMac.
  • Resolve the macOS Big Sur is running slow problem efficiently: It makes your system faster in a few clicks.
  • Very simple to use: There is no tech knowledge required to use this tool.
  • Wide compatibility: This tool is compatible with all macOS versions, including macOS Big Sur.
  • CleanMymac is trustworthy: Many renowned tech sites, such as Cult of Mac, MakeUseOf, Macworld, etc., trust and recommend this tool.

What Does This Tool Do for Optimizing and Speeding Up Your Device?

  • CleanMyMac cleans up more than 40 useless or junk files safely and selectively.
  • This tool can find and delete big files featuring more than 50MB.
  • It even deletes duplicate files to free up that wasted space.
  • CleanMyMac speeds up your system with four options.
  • It erases private files on your system to prevent privacy leaks.
  • This tool removes unwanted extensions and applications easily.
CleanMyMac SmartScan

CleanMyMac is simple to use. Now, take the option of ‘Speed Up Your Mac‘ for fixing the macOS Big Sur slow issues using this professional tool.

2. Employ Activity Monitor for Disabling Power-Hungry Applications

On Mac, power-hungry applications use up various resources and keep up the CPU and RAM of your Mac. It leaves little storage space for macOS to function correctly. As a result, you face the macOS Big Sur slow issue, where your system heats up quicker than usual.

Users can employ the activity display to stop such applications from affecting the speed of their operating system. To do so:

  • Visit ‘Applications‘ and choose ‘Utilities.’
  • Double-tap on the ‘Activity Monitor‘ tab.
  • Go to the ‘Memory‘ or ‘CPU‘ to find out which applications take up more storage on the memory and CPU.
  • Now, visit the ‘Memory‘ button to discover which applications take up more memory.
  • So, if you like to stop such applications, tap on ‘X‘ present at the top.
Disable Activity Monitor to fix macOS Big Sur slow

3. Optimize User-Interface Experience

In the new macOS Big Sur update, the interface features various customizable settings. Plus, it makes the old Mac versions run slower.

So, more important effects like transparency affect the available resources in your system.

As a result, you face the macOS Big Sur slow issue on your system. To prevent this:

  • Visit ‘System Preferences‘ and choose ‘Accessibility.’
  • After that, choose ‘Display.’
  • Tap on the box next to ‘Reduce Motion‘ and ‘Reduce Transparency.’
Optimize User-Interface Experience to fix macOS Big Sur slow

4. Restrict Login Apps and Items

Launch applications and items are running in the background after you log into the Mac. This results in issues like macOS Big Sur running slowly. Disabling both can help in improving the performance of your macOS.

To resolve the macOS Big Sur slow issue, follow the steps given below:

  • Visit ‘System Preferences.’
  • Then, choose ‘Users and Groups.’
  • After that, visit the tab ‘Login Items.’
  • Choose it and tap on the ‘-‘ (or minus) tab to remove any application.
Restirct Login Apps and Items

However, disabling every launch item and application is quite time-consuming. To perform this task in some clicks, use CleanMyMac. This performs the job automatically for you!

5. Make Temporary Admin Account Agents

When you make a temporary admin account, it fixes various performance-related issues. So, this can help fix the macOS Big Sur slow problem on your Mac.

Go through the instructions below for creating one:

  • Visit ‘System Preferences.’
  • Now, select ‘Users and Groups.’
  • From there, tap on the icon of a lock.
  • Enter the name and passcode of your admin account to confirm the permission.
  • Tap on the button (+).
  • Choose the ‘Administrator‘ option from the given menu.
  • Put in the needed details and tap OK.
  • Next, sign out of your current account and log into the new one.
  • Look at the performance of your Mac in the ‘Daily Usage‘ tab.
  • If this functions fine, there were problems with the earlier account’s settings or files.
  • Users can use diagnostic tools to fix the macOS Big Sur slow issue.
Make Temporary Admin Account Agents

6. Reset PRAM/NVRAM and SMC

On your Mac, PRAM and SMC control low-level features but are essential too. However, these files can get corrupted.

As a result, users may have to deal with the macOS Big Sur running slow problem.

Users can reset controllers to improve Mac’s performance in the following manner:

Resetting PRAM/NVRAM:

  • Turn off your Mac.
  • After that, switch on the Mac.
  • After hearing the startup sound, you need to hold the keys ‘Option,’ ‘Command,’ ‘P,’ and ‘R‘ together. Hold them until the system restarts.

Resetting SMC:

  • Turn off your Mac.
  • Now, disconnect its power cord.
  • After 20 seconds or so, reattach its power cord.
  • Then, hold the tabs ‘Shift,’ ‘Option,’ ‘Control,’ and ‘Power‘ together for around 10 seconds.
  • Now, release all tabs and boot the system.
Reset SMC and NVRAM to fix macOS Big Sur slow

7. Fix your Slow Wi-Fi Speed

An inadequate or slow Wi-Fi connection might make your system run slow after you have updated it to Big Sur. On your Mac, many factors can cause the issue of poor Wi-Fi connection.

Restart the router to fix the slow Wi-Fi problem. If this does not work, relocate the router to bring it closer to your system for better signals.

Also, you can check the DNS settings on the Wi-Fi. This exhibits some names corresponding to some numbers. Now, these refer to the devices’ names and IP addresses.

For resolving the macOS Big Sur slow Wi-Fi issue:

  • Visit ‘System Preferences.’
  • Tap on ‘Network‘ from the ‘Control Panel.’
  • When you’re connected through a cable, choose ‘Ethernet.’
  • Choose the tab ‘DNS‘ from the new tab.
  • Now, add a new DNS server by clicking on the (+) tab.
  • Add a Google DNS server by entering IP addresses like “” and ““. So they can be accessed first. Thus, it helps as these servers are quite faster.
DNS Settings

8. Upgrade All of Your Mac’s Applications

So, is your macOS Big Sur running slow? Updating all applications and software on your system helps speed up your operating system.

Follow some simple steps for accomplishing this task:

  • Tap on the Apple icon to open the menu on your Mac.
  • Select the option ‘App Store.’
  • After that, you will come across offered updates for all the applications.
  • Next, update the applications by tapping on the tab ‘Update‘ present next to these apps.
Upgrade mac apps

9. Run the Hardware Test

If there is something erroneous with any hardware part of your Macbook, your Mac may slow down. Thus, you face the macOS Big Sur slow problem after updating the Mac to Big Sur.

Run a Macbook hardware examination to examine whether the system hardware is functioning correctly.

To run this hardware assessment on the system, go through the instructions listed below:

  • Firstly, turn off your Mac. Then, disconnect all peripherals.
  • Now, turn on the Mac. Tap on the ‘D‘ key from the keyboard.
  • An Apple Hardware Test or Diagnostic Tool will appear on your Mac’s screen. This will run a test for the system. After a while, this will show the detected results.
  • If there is some problem with the hardware, you will receive an error code on the MacBook’s display.
Run Hardware Test

10. Downgrade macOS Big Sur to Catalina

Are you still struggling with the macOS Big Sur running slow issue? If nothing works for your Mac and your system is still functioning slowly, then downgrade it. It is best to downgrade your system to the earlier macOS Catalina.

To perform this action, follow the steps given below:

  • Firstly, erase the hard drive of your Mac.
  • On the Mac, reinstall the macOS Catalina.
  • Restore the backup from the previous macOS.
Reinstall macOS Big Sur


1. Why is my Mac running slow after updating to macOS Big Sur? After updating to macOS Big Sur, various factors can contribute to slower performance, including insufficient disk space, outdated hardware, resource-intensive applications, misconfigured system preferences, and incompatible software.

2. How can I free up disk space on my Mac? You can free up disk space on your Mac by removing unnecessary files, uninstalling unused applications, and clearing cache and temporary files.

3. Should I upgrade my Mac’s hardware to improve performance? If your Mac is running on outdated hardware, upgrading certain components like RAM and storage can significantly enhance performance.

4. How can I disable startup items on my Mac? To disable startup items on your Mac, go to System Preferences > Users & Groups > Login Items and uncheck the items you don’t want to launch at startup.

5. Is it safe to reset SMC and NVRAM on my Mac? Yes, resetting the System Management Controller (SMC) and Non-Volatile Random-Access Memory (NVRAM) is a safe troubleshooting step that can help resolve various system-related issues, including slow performance.


So, this is how you can fix your Mac’s macOS Big Sur slow issue. This new Big Sur update is quite great.

However, some users face the macOS Big Sur running slow problem on their Mac systems. There is nothing to worry about, as you can improve the performance of your Mac by following the above methods.

We recommend you go with CleanMyMac. This tool effectively speeds up your system. It can even make the Mac run faster and more effectively than before. Try this amazing tool by getting its free version!


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