Summary: This page collects solutions to over 15 updates problems of macOS 11 Big Sur, troubleshooting issues like updates failure, data loss, abnormal battery drain, frozen boot screen, etc.

The newly released update, macOS Catalina, is available to users who are running OS X 10.9 (Mavericks) or later on their Mac. With this latest iteration, Apple replaces macOS Mojave sporting newly updated features. Make your old Mac support macOS Catalina. Older Mac owners don’t have to worry. It’s not the end of the world. There’s a patch that lets you install Catalina to Macs that are not officially supported. The patch is known as DosDude Catalina Patcher. DosDude Catalina Patcher is a third-party tool, meaning Apple does not develop the tool. While you’re still on macOS Catalina, if you open System Preferences and select Software Update, you’ll see the icon for macOS Big Sur with an obvious “Upgrade Now” button. But we don’t want to upgrade to macOS Big Sur just yet. Software Update macOS Big Sur. If you are using a Mac notebook, you need to plug it into AC power. Download macOS Catalina. If you’re using macOS Mojave, then you need to update software to get MacOS Catalina. To do this, click Apple menu System Preferences, and then select Software Update. Check this article to know how to update software on Mac. Convert the volume to APFS 4. Restart the installation. Big Sur Update Stuck on Gray Screen. It's not always a gray screen, as strange as that may sound. The 'gray screen' problem can also manifest itself as a black screen, space screen with Apple logo, a spinning gear, a spinning globe, or a prohibitory sign.

macOS 11 Big Sur (not the expected macOS 10.16) is a terrific update from Catalina, with multiple new features and an overhauled look. Though not as buggy as macOS Catalina, it doesn't necessarily mean Big Sur is flawless. macOS update problems are of great concern for many users still. You can downgrade macOS Big Sur to macOS Catalina or face the issues and solve them.

As far as we are concerned, over 15+ upgrade problems are affecting macOS 11 Big Sur.

• macOS Big Sur Installation Problems:
• 1. macOS Recovery mode not working
• 2. Data issues
• 3. Fail to download macOS Big Sur
• 4. Can't install macOS 11 on Mac
• 5. Older Macs incompatible and bricked
• 6. macOS Big Sur won't boot up
• 7. macOS Big Sur stuck in a boot loop
• 8. Mac stuck in Recovery mode

• macOS Big Sur Performance issues:
• 9. Bluetooth is not working
• 10. Network is not working
• 11. Mac slow & hot after macOS 11 update
• 12. Shortter battery issues
• 13. Mouse problems
• 14. Apps quit unexpectedly in macOS Big Sur
• 15. Can't use Airdrop in macOS Big Sur
• 16. External hard drive read-only on Mac

Now, let's check them one by one and dig for a solution.

1. Data issues in macOS 11 update

In latest 10.15 Catalina and macOS 11, Apple splits the startup disk into two separate volumes, System and Data. It makes data backup difficult especially those apps making (and restoring) bootable backups.

Therefore, it's always recommended to back Mac files up before every major macOS update using the built-in Time Machine.

If you upgraded to macOS Big Sur on a Mac that uses a Time Capsule or other network storage device as the backup destination, your existing backups are also upgraded and can be used only on macOS Big Sur. New backups that are created can be used only on macOS Big Sur.

If you are using a third-party software to back up, then you need to wait until it's ready for macOS 11.

How to restore or recover lost files after macOS Big Sur update?

Though Apple has made a precaution that important files might get lost if the macOS update is interrupted, many of us still forget to back up our Mac with the built-in tool Time machine. As a result, private data like photos and documents might have gone once after updating the system.

My Macbook Pro Will Not Update To Catalina

How to fix:

1. If you have backed up your Mac to an external hard drive with Time Machine, you can simply restore the Time Machine backups.
2. How to restore Mac files from Time Machine backup?
3. If you don't have any backup while the failed macOS Big Sur stops your Mac from booting up, you can try iBoysoft Data Recovery for Mac to get files off Mac that won’t turn on.
4. How to recover data from Mac that won't turn on?

How to Find Missing Trash & Junk Folder in macOS Big Sur Mail?

Fix problems in Mac Mail after macOS Big Sur update, including Trash and Junk folder missing from the Mail sidebar and other so-called Mail 'bugs'. Read more >>

2. Fail to download and install macOS Big Sur

macOS 11 fails to download with some messages like 'The network connection was lost', 'Installation failed', or 'there is not enough space'.

Can't download macOS Big Sur or take a too long time, what to do?

With a large size of over 12 GB, it might take a while to download macOS 11. However, if downloading the software takes time more than you expect (like hours), some things go wrong. In some cases, messages like 'macOS Big Sur download has failed' might cast a chill over you.

How to fix:

• Check your Internet connection (either an Ethernet or WiFi) and make sure it's fast and stable enough.
• Make sure the task of downloading macOS software update is working fine. Or you can restart your Mac and try it again.
• Make sure you have made enough room for the software on the target disk.

Can't install macOS Big Sur on Mac, why?

A successful macOS software update is not as easy as you think. After downloading, if macOS Big Sur won't install on your Mac machine, all your effort might be in vain. Your Mac may freeze on setting up your Mac, and some older MacBook Pro machines even get bricked by macOS Big Sur.

This could be a result of installing into the same APFS container as previous versions of macOS Catalina 10.15. Another possible reason for 'macOS Big Sur Cannot Be Installed On This Computer' is that macOS 11 simply is not compatible with your Mac (e.g. iMac 2020, Retina 5K, 27-inch).

How to fix:

• If you can't upgrade from macOS 10.15 Catalina to Big Sur, you need first update to 10.15.6 before installing macOS Big Sur.
• If your Mac is T2-secured, to install macOS Big Sur, you need to boot your Mac to macOS Recovery mode > Utilities > Startup Security Utility, and then make sure the Secure Boot option is NOT set to 'No Security'.
• If you receive the error 'you may not install to this volume because it is currently being encrypted' when selecting a disk to install macOS Big Sur, wait for the disk encryption to finish and then disable File Vault in Safe Mode (Apple menu > System Preferences > Security & Privacy > FileVault) before reinstalling.
• If you fail to upgrade to macOS 11 Big Sur and receive 'an error occurred applying the software update', try to restart with 'Command + R' or 'Command + Option + R', and then reinstall macOS in macOS Recovery Mode.
• If you fail to install the macOS software because the Mac goes sleep while preparing macOS Big Sur 11, you can simply adjust Energy Saver settings by Apple menu > System Preferences > Energy Saver and then try it again.

macOS Big Sur bricked some incomaptible Mac models

Another possible reason for 'macOS Big Sur Cannot Be Installed On This Computer' is that macOS 11 simply is not compatible with your Mac (e.g. iMac 2020, Retina 5K, 27-inch).

Make sure your Mac is in the list of compatible models. DO NOT install macOS Big Sur if you are using a MacBook Pro earlier than late 2013 and mid 2014. If it has already casued a problem, you need to reinstall macOS or downgrade the macOS to Catalina.

3. Startup issues after installing macOS Big Sur

After installing macOS Big Sur, the Mac will then automatically restart from the newly installed system. What comes along with is a repeated boot loop, restarting, black screen, and then loading macOS 11 Big Sur. But if any problems occur or any part of those gets stuck, the MacBook won't turn on.

Mac Not Upgrading To Catalina

You might see it stuck on the loading screen with an Apple logo, or return some symbols that you have never seen on your Mac, such as a flashing globe, a folder with question mark, pink screen of death, or a prohibitory icon. Finally, the macOS update just crashed and bricked your computer.

How to fix:

• Force your Mac to restart.
• Repair your Macintosh HD by booting into macOS Recovery mode > Disk Utility > First Aid.
• Restart your Mac to Safe Mode and reinstall macOS
• Erase your Macintosh HD and create an external bootable installer.

Related articles:

• How to fix Mac stuck on loading screen?

• How to fix Mac black screen after macOS Big Sur update?

• How to fix when Mac shows a flashing folder with a question mark?

• How to fix the prohibitory symbol at Mac startup?

• How to fix if Mac won't let you log in with right password?

Mac stuck in a boot loop after macOS update

Mac will restart for several times after macOS Big Sur update, so keep your Mac connecting to the power source during this process.

But if things do not go well after waiting, you can try these solutions:

1. Try to boot into safe mode. Some third-party software (Kernel Extension or a LaunchDaemon) installed on your Mac might be causing this issue, which can be isolated by Safe boot.

2. Reinstall macOS.

macOS Recovery Mode is not working in macOS Big Sur

Some experienced users may find that they can't boot into macOS Recovery mode to fix some issues with Command + R.

Then you can try Command + Option + R, or Shift + Option + Command + R.

If it's a Mac with Apple Silicon M1 chip, try to access macOS recovery and security options at startup by the on-screen Startup Manager

In the new system architecture, you can hold down the power button and access the new startup screen for recovery options like macOS reinstall.

Mac stuck in Recovery mode on Apple Silicon MacBook

The recent Apple Silicon MacBook (M1) was built-in with macOS Big Sur 11.0, while it may cause problems if you want to enable some system extensions in macOS Recovery mode for apps. The Mac will get stuck in Recovery mode and keep spinning.

To solve this problem, the only thing you need to do is to update your system to the new major update macOS 11.4 Big Sur.

Then you'll be able to access macOS Recovery mode again.

4. Poor Performance When Using macOS Big Sur

Fortunately, you succeed in downloading, installing, and booting from macOS Big Sur. But the experience in using this system maybe not as good as you expected. Read on and check what you can do when suffer from those problems.

How to fix if macOS Big Sur slows, freezes, heats the Mac?

It's one of the most common problems discussed in forums. macOS 11 Big Sur could lag your Mac and gets computers really hot, especially you are using MacBook Air and MacBook Pro that are relatively old. Before you downgrade from macOS Big Sur to Catalina, try the following things.

How to fix:

• Disable unnecessary login items by Apple menu > System Preferences > Users & Groups > Login Items.
• Quit processes or applications in Activity Monitor if your Mac freezes on the beachball.
• Quit or disable the Spotlight Search feature when a lack of system resources heats up your Mac.

Bluetooth is not working in macOS Big Sur

Bluetooth makes it easier when you work on your Mac with wireless devices in-between. So if the bluetooth is not available after macOS 11 update, try to:

For Bluetooth issues in macOS Big Sur, you can press Shift + Option and click the Bluetooth icon in the menu bar > Reset the Bluetooth module > OK > restart the Mac.

Network (WiFi) is not working in macOS Big Sur

The importance of the Network like WiFi connection goes without saying. Either of them could be not functional after upgrading to macOS 11.

For Network issues, you can go to System Preferences > Network > Wi-Fi > Advanced > Remove the connected WiFi connections > restart Mac and reconnect to the Network.

How to fix abnormal battery drain in macOS Big Sur?

For notebooks like MacBook Air and MacBook Pro, battery drain could be a hassle. However, macOS Big Sur could make your battery reach its low point faster than before, or in an abnormal way due to the running background wor.

• MacBook Pro not charging, what to do?

How to fix:

• Locate the programs that impact the energy most and get insights on energy saving in Activity Monitor > Energy.
• Reset SMC and PRAM after login to better manage power, battery, fans, and other related features.
• Check for your battery lifespan and charge circle count by Apple menu > About this Mac > System Report > Hardware > Power.

Mouse problems in macOS Big Sur

If you've installed macOS Big Sur and found your mouse no longer works, open up the ~/Library/Preferences/ directory in finder and select and delete the following files and restart your Mac to get the mouse working:

• com.apple.AppleMultitouchMouse.plist
• com.apple.driver.AppleBluetoothMultitouch.mouse.plist

5. Built-in or Third-party Apps Issues in macOS Big Sur

Software is one of the most critical parts using any computer, which includes built-in programs and third-party apps. In the new macOS Big Sur, software incompatibility could cause apps unexpectedly quit, kernel panic, or even the whole system crash.

Apple Menu bar disappeared in macOS 11 Big Sur, how to fix?

Strange but true, some users report that the Mac menu bar is missing icons such as the Clock, WiFi, Control Center, etc. This is reasonable as any new operating system could be glitchy. In this case, you can simply restart your Mac or follow these steps:

1. Step 1: Open System Preferences > Users & Groups.
2. Step 2: Click on Login Options and type your admin password.
3. Step 3: Disable the option 'Show fast user switching menu as'.
4. Step 4: Once the menu bar is back, go to System Preferences once again and select Dock & Menu Bar (the new preference pane that lets you show/hide controls).
5. Step 5: Disable Fast User Switching to remove it from Control Center.

External hard drve is read-only in macOS Big Sur

This is a long standing issue in macOS, not only in macOS Big Sur. That external hard drive is read only after plugging in to the Mac machine, which generally is caused by the Windows NTFS file system. So, if you can't write to your disks, check those things:

• Change device share permission by right clicking > Get Info > Sharing & Permissions
• Find an NTFS for macOS Big Sur software.

If it is other file system, read our article as below to fix it:

• How to solve external hard drive read-only without formatting on Mac?

Can't use Airdrop in macOS Big Sur, how to fix?

You might be unable to use Airdrop for files transferring and sharing in macOS 11. This could result from System Integrity Protection (SIP), which is a bug for macOS Big Sur beta. You can simply go to disable SIP.

• How to fix AirDrop not working?

There are many other software issues like software unexpectedly quit, and apps like VirtualBox, AdGuard, Chrome, and Steam won't response in macOS Big Sur. What we can advise is to downgrade to a previous system like macOS Catalina and Mojave, and do not upgrade to macOS Big Sur until it is released to the public in a stable condition.

Verdict

No one can guarantee that updating to macOS Big Sur is 100% safe, especially in the buggy stage that bursts out problems like:

• Data loss and macOS 11 update failure
• Startup issues after installing macOS Big Sur
• Poor performance when using macOS Big Sur
• Built-in or third-party apps issues

But what you can do is to back up your Mac files and get noticed possible problems. Then, when you want to upgrade to macOS Big Sur, you won't risk data loss and you are prepared for known issues and data recovery.

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We all know that it’s important to “stay patched, so you stay secure.” But macOS is making that a bit harder these days. Apple really wants you to upgrade to macOS Big Sur, but if you’re not ready for that big jump, it may be hard to notice that you have macOS Catalina and Safari updates to apply.

macOS Big Sur is a huge change and it’s usually a good idea to let the bleeding edge folks work out the kinks. It’s also not a bad idea to wait for Apple to make at least its first update before jumping on the new hotness. You may have applications that are not yet macOS Big Sur-compatible so be cautious with a big upgrade like this. I’m not a proponent of waiting a long time to upgrade to the latest OS but caution, especially on such a big change, is definitely warranted. While you’re waiting for the OS to stabilize, you want to keep macOS Catalina up to date, but Apple makes it difficult to see just how to do that.

While you’re still on macOS Catalina, if you open System Preferences and select Software Update, you’ll see the icon for macOS Big Sur with an obvious “Upgrade Now” button. But we don’t want to upgrade to macOS Big Sur just yet.

When I took the screenshot for this post, I actually had updates to macOS Catalina and Safari waiting for me, but it sure wasn’t obvious they were there.

Under the icon for macOS Big Sur, there was some smaller text that said, “Other updates are available” and blue link text that said “More info…”

Click on that tiny More info link to reveal the updates you really need to apply. In my example, I had macOS Catalina 10.15.7 Supplemental Update waiting, and the notes below clearly say that this update “improves the security of macOS.” There was also a Safari update to 14.0.1 which had some speed enhancements but also security fixes, including the removal of support for Adobe Flash. You really want this update!

Mac Will Not Update To Catalina

After you apply any Safari or macOS Catalina updates, the Software Update Preference Pane will still say “More info…” As shown below:

Can't Update Macos Catalina

But if you click the link now, it will take you to the Apple web page telling you about all the awesome features of macOS Big Sur. I presume this “More info…” link will change back to showing you security updates for macOS Catalina and Safari when new ones are available, so you’ll have to be vigilant and pay attention in looking for the updates.

I don’t like that Apple has made it so undiscoverable that security updates are awaiting us. I would really prefer that they had made two equally-obvious buttons, one to upgrade to macOS Big Sur and one to update macOS Catalina and Safari. They’re doing a disservice to the community by making it this hidden. As I said up front, I’m a big proponent of getting on a new OS when it’s practical to do so, but it is the user’s decision when to do it and shouldn’t be tricked into what could be a catastrophic upgrade.

Why Will My Mac Not Update To Catalina 10.15.7

Since you’re probably the family nerd if you’re reading or hearing this, please pass this post along to your friends and family so they stay patched so they stay secure.