macOS Big Sur Problems: How to Fix Common Update and Install Issues

Prepare

This part will provide details about the preparation to ensure that your upgrade to macOS Big Sur goes smoothly.

Check macOS Compatibility

See whether your Mac is available for macOS Big Sur.

Supported Mac devices:

MacBook 2015 or later
MacBook Air 2012 or later
MacBook Pro2012 or later
Mac mini 2012 or later
iMac2012 or later
iMac Pro (all models)
Mac Pro 2013 or later

Make a Backup

Back up your Mac and iTunes Media Library via Time Machine or third-party backup software.

Method 1: Time Machine Backup

Connect an external storage deivce to Mac > Select it as backup disk...
More details

Method 2: Automatic Backup

Run EaseUS Todo Backup on Mac > Enjoy a perfect copy plan...More details

Hardware Requirements

Connect Mac to a reliable Internet or WiFi.
At least 4GB memory, 12.5GB free space.
At least 50% battery on Mac.
De-activate VPN before downloading the update.
Remove third-party 'kext' files. Some of these are known to cause issues.

Update

This part will provide details about the preparation to ensure that your upgrade to macOS Big Sur goes smoothly.

Upgrade from macOS Mojave: Choose Apple menuSystem Preferencesclick Software Update

Open macOS Big Sur page on App StoreClick Get button or iCloud Download icon.

Open Apple menuChoose System PreferencesSelect Software UpdateChoose Automatically keep my Mac up-to-date.

Troubleshooting

Are there any problems with macOS Big Sur 11.0 update? Each release of the regular security update is meant to fix the earlier version bugs. However, most of the time it brings its own fresh set of problems.

Download and Installation Problems with Big Sur

Common Problems After Installing Big Sur

Problems Running Apps in Big Sur

At the first stage of downloading the operating system, users would possibly get stuck at updating taking a century to complete, not enough free disk space to install the update, or Mac doesn't boot normally from the newly installed operating system.

1. Big Sur Download Takes Forever

Step 1. Check Apple Server status and make sure macOS Software update is 'green'.
Step 2. Make sure your Wi-Fi is strong or use a wired internet connection.
Step 3. Cancel the download if it is stuck for a long time by clicking on the 'X' next to the 'downloading new updates….' message.
Step 4. Switch your DNS to 8.8.8.4 and retry downloading the macOS Big Sur.

2. Install Doesn't Complete, Stuck at "xx minutes remaining"

Step 1. Shut down, wait a few seconds, then restart your Mac.
Step 2. Quit all running apps or programs from your Mac. To do this, simultaneously press the Option, Command and Escape (Esc) on the keyboard. The Force Quit window will show up, select the app and click Force Quit to close it.
Step 3. Restart/refresh your internet connection by navigating to System Preferences > Network.
Step 4. Free up some storage space by deleting all unused apps and files from your Mac. You can also transfer some large files from your Mac to external devices.
Step 5. Install in Safe Mode. Press the Power button and hold down the Shift key to start the Mac up in Safe Mode. Open App Store and update your apps while in Safe Mode. Reboot your Mac.
Step 6. Reset the NVRAM. If Safe Mode doesn't work, restart the Mac and hold down Command, Option/Alt, P and R. This will reset the NVRAM. Wait until the computer restarts and wait to see if it starts updating.
Step 7. Hold down Command + R at startup and restart the Mac in Recovery Mode to reinstall macOS. There, choose the "install new OS" option to start.
Step 8. If the install fails at the last step every time showing "xx minutes remaining", the user account might have corrupted. You can create a new admin account on your MacBook to get rid of this problem.

3. macOS Could not be Installed on Your Computer Error

Step 1. Restart your Mac and retry the installation.
Step 2. Set your Mac to the correct date and time by going to System Preferences > Date & Time to correct it. Click the Padlock and enter your administrator password, then choose to Set date and time automatically.
Step 3. Create enough free space (around 20GB) for macOS Big Sur to install.
Step 4. Repair your startup disk. Open Disk Utility from the Utilities folder in Applications. Select your Mac's startup disk, usually Macintosh HD, then click First Aid. Run First Aid, Disk Utility will start scanning your disk for errors and repairs whatever it can.

Chances are that the seemingly successful update will also cause unusual boot or connection issues. Just in case you're suffering from the problems here, we've brought you complete solutions.

1. Mac Won't Boot After macOS Big Sur Installation

Step 1. Make sure your MacBook is adequately charged. Also, try to remove the power cable that used to charge your MacBook. Press and hold the Power button for at least 10 seconds. Again Take a power cable and Plugin. Now Hold Down Power button for 7 seconds. This will help to hard boot your Mac.
Step 2. Reset SMC/PVRAM settings. On your MacBook keyboard, press and hold the keys Shift + Control + Option + Power. After that only press the power button to turn on the MacBook Screen.
Step 3. Start in Safe Mode. Press and hold down the Power + Shift keys together. Then, release the Shift key when the login page appears on the screen.
Step 4. Delete kext files. If your Mac doesn't start and display a black screen and Apple logo for hours, reboot your Mac into Safe Mode, open up Terminal from your Utilities and type the command: mkdir ~/Extensions-Backup && sudo mv /Library/Extensions/* ~/Extensions-Backup/. Delete all the third-party kext files and restart the Mac.
Step 5. Recover data from none bootable Mac hard drive. Download EaseUS Data Recovery Wizard for Mac, create a bootable USB stick and perform a full data recovery.

2. Inability to Log in to the Computer

Step 1. Turn off the Mac and turn in back on.
Step 2. Create a new admin account.
Step 3. Reset your admin account using a Terminal prompt. Restart your Mac and hold down the Command + S keys on your keyboard. Type the commands inot the terminal window and press Enter:
/sbin/mount -uw
rm / var/db/.applesetupdone
Step 4. Close the Terminal and log in your account.

3. Problems with peripherals

1. For the keyboard related issues, if your Mac is a laptop, restart the Mac. When it gets to the Finder, close the MacBook. Wait for a few seconds and then open it again.
2. Delete the mouse plist. If it's the mouse that doesn't work properly, go to the Library > Preferences and find the two plist files and then restart the computer:
com.apple.AppleMultitouchMouse.plist
com.apple.driver.AppleBluetoothMultitouch.mouse.plist.
3. Remove the Bluetooth plist. This can correct a spotty bluebooth connection. In Preferences, delete the bluetooth plist file and restart the computer: com.apple.Bluetooth.plist.
4. Remove the Finder plist. If the Finder crashes after installing Big Sur update, go to remove the plist file in the Preferences folder and restart: com.apple.finder.plist.

4. macOS Big Sur Runs Slowly After Install

Step 1. Stop/decrease the number of applications launching automatically at startup. Click the Apple log and select System Preferences > Users & Groups > Login Items. Highlight any apps that don't need to open when you log in and click the "-" button to disable its launch.
Step 2. Clean up useless large files and duplicated files that take up unnecessary disk space. Download EaseUS CleanGenius and let it do a spring cleaning on your Mac drive.

How to Downgrade

If the new macOS like Big Sur is not working on your Mac, macOS fails to boot after update, or your Mac has App compatibility issues, you can downgrade the macOS and keep your Mac to stay safe with the best one.

Revert to a Previous macOS Version

Note: If you used Time Machine to back up your Mac, you can easily revert to a previous version of macOS when you met troubles after installing an update.

Step 1. On your Mac, choose Apple menu , click "Restart".
Step 2. After Mac restarts, press the Command and R keys until the Apple logo appears.
Step 3. Select Restore from a Time Machine Backup, then click "Continue".
Step 4. Select your Time Machine backup disk.
Step 5. Choose the most recent backup that occurred before you installed the new macOS.
Step 6. Follow the onscreen instructions to revert to a previous macOS version.

More details 

Reinstall macOS from macOS Recovery

Note: If you failed to backup macOS using Time Machine, you can reinstall the macOS that was installed on your Mac via macOS Recovery.

Step 1. Turn on your Mac and press the Command and R keys until the Apple logo appears.
Step 2. Enter your administrator password and click "Continue".
Step 3. Select Reinstall macOS and click "Continue" on the macOS Utlities window.
Step 4. Follow the onscreen instructions to complete the prcess.

More details 

Frequently Asked Questions About macOS Update

1. Is my Mac too old to update?

When you are using an old Mac and hope to update your Mac with the latest version of macOS, first, you need to make sure if your Mac is too old to run the updated software.

Apple advices installing macOS Big Sur if you are using the following Macs:

MacBook models from early 2015 or later
MacBook Air models from mid-2012 or later
MacBook Pro models from mid-2012 or later
Mac mini models from late 2012 or later
iMac models from late 2012 or later
iMac Pro (all models)
Mac Pro models from late 2013

Apple advices installing macOS Mojave if you are using the following Macs:

Mac models from 2012 or later
iMac Pro (from 2017)
MacBook models from 2015 or later
MacBook Pro models from 2012 or later
MacBook Air models from 2012 or later
Mac mini models from 2012 or later
Mac Pro models from late 2013

If your Mac is older than 2012, it won't offically be able to run Big Sur or Mojave. If your Mac computer is a 2009 or 2010, or even older version, Apple suggests that you stay with the current macOS or Mac OS X.

2. What is the latest version of macOS?

Apple's newest Mac operating system is macOS 11.0, also known as macOS Big Sur. This operating system was anounced on June 3, 2019 and officially published on October 7, 2019.

An upcoming macOS was anounced on June 22, 2020 and it's highly possibly to be released in2020 this automn. Follow to find out which macOS your Mac is using.

3. Can I upgrade from Sierra or High Sierra to Catalina?

It depends. If you are using one of these computers with Mac OS X Mavericks or later, you can install macOS Catalina:

MacBook introduced in 2015 or later
MacBook Air introduced in 2012 or later
MacBook Pro introduced in 2012 or later
Mac mini introduced in 2012 or later
iMac introduced in 2012 or later
iMac Pro (all models)
Mac Pro introduced in 2013 or later

Also, your Mac needs at least 4GB of memory and 12.5 GB - 18.5GB of available storage space while upgrading from Sierra or High Sierra to Catalina.

Note that only Mojave users can directly update to macOS from Software Update. Older macOS users can open the Catalina page on the App Store: Get macOS Catalina. Then click the Get button or iCloud download icon.

4. How do I recover files after updating my Mac?

If macOS update deletes files from your Mac, you can restore lost files from your backup using Time Machine Backup, iCloud backup, or APFS Snapshot.

If you don't have a backup, don't worry. You still have a chance with the help of using professional data recovery softare, like EaseUS Data Recovery Wizard for Mac.

Check out how to recover files if macOS Big Sur/Catalina or Mojave update deleted everything on your Mac.

5. How do I fix Time Machine stuck on preparing backup?

When Time Machine takes forever, freezes or stuck on “Preparing Backup” while you attempting to use it back up files on Mac, you can try the following steps to get rid of this issue immediately:

Step 1. Stop the current Time Machine on Mac.

When the progress bar disappears and it no longer says "preparing backup", it means that you have successfully stopped the currently failed Time Machine backup attempt.

Step 2. Remove the .inProcess File.

Open Time Machine drive, navigate to “Backups. backup” folder, search “.inProgress” file and delete the "xxxx-xx-xx-xxxxxx.inProgress" file.

Step 3. Prevent Spotlight from indexting Time Machine backup.

Step 4. Restart Mac.

6. Are all macOS updates free?

According to Apple, upgrding is free. Basically, all updates of full Mac OS versions are free.

If you are planning to upgrade to the full version of macOS Big Sur, you can do it now. It's free.

As you know that before the publick beta of macOS was released, there was macOS Developer Preview version. If you are a developer and need to use this option, you are required to enroll in the Apple Developer Program and this will request payment.