Big Sur

21 Jul 2021

Apple released macOS 11 version 11.0.1, "Big Sur," on 12 Nov 2020. It is a free update to 10.15 Catalina. This note describes how to update a computer from an older version of macOS to Big Sur. (The OS is called "macOS 11" instead of "macOS X". Whoopee.)

The latest version of macOS is version 11.0.1, "Big Sur", released on 12 Nov 2020.

Apple released macOS 11.1 on 14 Dec 2020 with support for AirPods Max, plus new features for Apple TV, Apple News, App Store, iPhone Apps on M1 Macs, Photos and Safari, and bug fixes.
Apple released macOS 11.2 on 01 Feb 2021 improving Bluetooth and fixing serious security problems.
Apple released macOS 11.2.1 on 09 Feb 2021 fixing charging problems on 2016 and 2017 MacBook Pros, and serious security problems with sudo and graphics.
Apple released macOS 11.2.2 on 25 Feb 2021 fixing problems M1 Macs had with certain USB-C hubs and docks.
Apple released macOS 11.2.3 on 09 Mar 2021 fixing a security problem with Web content.
Apple released MacOS 11.3 on 26 Apr 2021 fixing more security problems and adding support for new devices.
Apple released MacOS 11.3.1 on 03 May 2021 fixing more security problems.
Apple released MacOS 11.4 on 24 may 2021 fixing more serious security problems and adding support for new devices.

There is a bug in the Big Sur installer that will brick your Mac if you try to install witnout enough free disk space, according to as of 09 Feb 2021. They say this bug is present in macOS 11.2 and in the 11.3 beta.

(I have not installed Big Sur on any computers.)

Ars Technica published macOS 11.0 Big Sur: The Ars Technica review on 11/12/2020.

Howard Oakley wrote an article on APFS changes in Big Sur.

Graham Needham has a useful article, macOS 11 Big Sur Frequently Asked Questions FAQ.

Michael Tsai published a review of Big Sur in May 2021. It sounds horrible. Mail bugs, Save dialog failures. External drive problems.

Big Sur ships with new Macs.

Features of Big Sur

Some applications developed for iOS can also run on Big Sur; this may make more apps available for the Mac. This feature is called "Catalyst."

Big Sur cryptographically signs every file on the read-only file system partition (that was introduced in Catalina). The signatures are checked when files are loaded, and the bootloader checks that all the hashes are correct at boot time. This should make it more difficult for malware to patch the OS.

Should I Install Big Sur?

Show Stoppers

Serious installation failure leading to bricked computer. See above. Check MacInTouch for the latest status.

Box seems to have problems on Big Sur.

Super Duper is unable to make a bootable backup for Big Sur on M1 Macs.

Installation Problems

Needs more disk space than Catalina.. about 3GB.


What you Should Do Now to Get Ready for Big Sur

Who Can Update

Not everyone can use the new OS version.

Plan your install

When you decide to install Big Sur, do it carefully. You may find that there are issues that affect you: do your homework. Check MacInTouch to see if there are problems with macOS 11.0 that affect you.

Make sure you back up your entire disk before starting to install Big Sur. Preferably to more than one place.

Make a list of the hardware you depend on, and search the web to check that each device will work. Older printers and scanners can have issues.

Leave yourself enough time. Upgrading will tie up your computer for a big part of a day. Installing takes an hour or two, but then your computer will be very slow until it re-does the Spotlight index and does a big backup up to Time Machine.

Issues with Apple Silicon ARM processors

Here is an article about the new Apple Silicon machines with the M1 chip from Ars Technica.

Particular issues before upgrading

Because Big Sur does some important restructuring of the file system, to provide the immutable system partition, if you find problems with Big Sur, you can't go back to a previous OS without wiping your hard drive and reloading the whole thing. Do an extra full clone backup of your disk before upgrading, and save that backup until you're sure you will keep Big Sur.

Big Sur requires that native ARM code must be signed to execute. This does not require interaction with Apple or a developer license -- it just checks that compiled ARM object files have not been patched.

Here is a partial list of minimum program versions needed for Big Sur. For other programs, check product websites.

ProgramMinimum VersionNotes
Aquamacs3.5graphics issues
Audacity2.3.264-bit at last
Adobe PhotoshopCC Photoshop CC is $120/yr. See below. (ARM supported.)
Adobe IllustratorCC Illustrator CC is $240/yr. See below. (ARM supported.)
Adobe AcrobatCC Acrobat CC is $180/yr. See below. (ARM not supported yet.)
Apple XCode12.2 free with registration; also install Command Line Developer Tools
Little Snitch5 A new version of Little Snitch is required for Big Sur. Furthermore, some Apple traffic such as Maps and ads don't show in Little Snitch. This sucks.
MacPorts2.7.1 for Big Sur free
Microsoft Office2019 $123
Onyx3.7.6 free
Super Duper3.5 for Big Sur is in beta Cannot make a bootable backup with Super Duper.
Brother P-Touch Editor5.1 not supported

Adobe: Renting Instead of Buying

Adobe no longer sells regular application versions of Photoshop, Illustrator, and Acrobat. Instead they rent you a Creative Cloud subscription. Stop paying, the apps stop working. They tell you that one advantage is that you'll get bug fixes and new features whenever they decide to release them. (There are a lot of tricky deals, initial teasers, different bundles. You could pay $20/app/mo or $600/yr for all CC apps, plus $180/yr for Acrobat. Adobe also sells Photoshop Elements 2020 and Premiere Elements 2020 as non-cloud applications for $100 each one-time, or both for $150.)

There are alternatives to Adobe products. I am using Affinity Photo and Affinity Designer. I need a replacement for Adobe Acrobat: PDFPen ($80) is looking attractive. There is a program called PDF Expert but its web site does not say how much it costs. I am not going to install it just in order to find out.

Microsoft: Renting Instead of Buying

Microsoft wants to rent you "Office 365" for $70/yr, $100/yr for up to 6 people. You can still buy a "forever" Home and Student version of Office 2019 for about $130.

Quicken and Banktivity: Renting Instead of Buying

Quicken has moved to a rental model also. There are various versions, Starter, Deluxe, Premier. Banktivity 7 works for me and is not rental software. Update: Banktivity is going to a subscription model as of 2021. Shucks.

Sony Alpha Support

I bought a Sony Alpha 6300 camera a few years ago. One feature I liked was the ability to upload photos from the camera to my Mac using WiFi and Sony's PlayMemories software.

Sony's PlayMemories software for the Mac was 32-bit. It is not supported on Big Sur. Instead, you have to install the Sony Imaging Edge app on a smartphone, and then transfer the pictures to your Mac. This method did not work at all until March 15, 2020, when an update for the Sony Imaging Edge smartphone app was released. I was able to transfer a photo to Mojave, but it takes multiple steps and the Help and website are extremely hard to understand.

Sony made Imaging Edge software available for the Mac about July 2020. In August 2020, I installed Imaging Edge for the Mac on Mojave, but it does not support the wireless connection mode for my camera, which worked with PlayMemories. To upload pictures to my Mac, I have to first send them by WiFi to my iPhone and then send them to the Mac; or I can connect the camera to my Mac using an USB-2 cable, or pull out the SD card and insert it into a Mac SD card reader. Uploading pictures is much more finicky and time consuming that it used to be.

I am very disappointed with Sony's Mac support. Sony has broken my camera. Makes me think of Lily Tomlin's Ernestine: "We're the Phone Company and We Don't Have To."

Installing Big Sur

(I have not installed Big Sur yet, so everything below this point will need updating when I do.)

  1. Clean up and update software before installing.
    • (If your Mac is running a very old version of OS X, you must install Snow Leopard 10.6.8 first, in order to get a version of Apple App Store that can download Big Sur. Here is Apple's how to upgrade page.)
    • You can download the Big Sur Installer from  ► System Preferences...=>Software Update. It is free. This downloads a large file, the Big Sur Installer, to your disk. You can create a bootable installer volume on a USB key using these instructions. (But see the TidBits article "Previously Downloaded OS X Installers No Longer Work".) Apple's license terms say you can update all your computers with one purchase.
    • Get the applications on your computer ready for 11.0: apply the latest fixes.
    • Delete junk files. Carefully.
    • Delete Safari, iTunes, and Firefox caches, so your backup will be faster.
    • If you have customized your desktop background or screensaver, write down your settings. Some Apple-provided pictures may not be available in the next version.. make a safe copy of anything you will want after upgrading.
    • Empty the Trash.
    • Clean up damaged and duplicate fonts.
    • Have your software license keys handy in case you have to re-authorize products.

    For Programmers

    • If you use MySQL, back up your databases with mysqldump databasename > db.sql. Then stop MySQL.
    • If you use Apache, save a copy of /etc/apache2/httpd.conf.
    • If you installed modules via CPAN, Macports, or Fink, make a list of them. In a Terminal window, type
      perldoc perllocal | grep :: > cpan_modules.txt
      port -qv installed > macports_packages.txt
    • The best way to handle Macports is to uninstall all the old ports and reinstall after updating the OS. After you list your installed ports, type
      sudo port -fp uninstall installed
      in a Terminal window.
  2. Backup and prepare.
    • BACK UP YOUR HARD DRIVE to an external disk. I used SuperDuper to clone my whole drive. Some cautious people make two backups.
    • If you are using an anti-virus product like Microsoft Defender ATP, disable it, or installation will fail. Some anti-malware programs see the utility that converts HFS to APFS as malware, and prevent it from running. Since most anti-virus software is tightly integrated with the operating system, you may have to install a Big Sur-specific version of your software after installing Big Sur anyway. Check with the maker of your software.
    • If you installed a third-party Solid State Disk (SSD), check the manufacturer's website to see if you need to update its firmware to work with Big Sur.
    • If you connect your Mac to the network using WiFi, select  ► System Preferences...=>Network=>Advanced and delete any WiFi networks you don't want to use. (If you don't, your computer may connect to a very slow network during installation, which will slow down your install.)
  3. Install
    • If you use a wireless mouse or keyboard, put in fresh batteries.
    • Set screen saver to NEVER, and turn off Time Machine.
    • Dismount and unplug or power off external drives.
    • Restart your computer. (I've had problems where my computer hangs on shutdown. Restarting seems to fix it for a while. Don't want this trouble when installing a new OS.)
    • Run the Big Sur (macOS 11.0) installer. If you downloaded it, use that copy. Or you can just select  ► System Preferences...=>Software Update and install by clicking on the link.
      • If FileVault is enabled on your computer, the installer will ask for a password to unlock the disk.
      • The installer will run for about 15 minutes, then reboot, then run for about an hour, then reboot again. Might ask for your password again.
      • The "time remaining" will show wildly varying estimates as the installer proceeds.
      • Don't panic if you see a gray screen with "30 minutes remaining" for an hour. Just let it run.
      • Eventually you will be presented with a login screen; enter your password.
      • You will see a window about privacy.
      • Next you will be asked if you want to send analytic information to Apple.
      • Then you will be asked if you want light mode or dark mode appearance. (You can change this later.)
      • Then the system will display your desktop. All your files and applications should be there.
    • If Big Sur asks you if you want to "enable Desktop and Documents folder syncing to iCloud," the safest thing to do is to say NO. If you say YES, these folders will be backed up in iCloud and available on all devices, which you may not want, and saying YES may also enable "Optimize Storage" without asking, which will delete files from your computer's drive if it gets too full. Adam Engst's TidBITS article on Optimized Storage is very helpful.
    • Select  ► System Preferences...=>Software Update and  ► App Store... to make sure you are up-to-date with the latest versions of Apple software. Then run it again to make sure all software is updated. (might take another hour) This step may find additional OS and application updates.
    • Do a "smoke test" to verify that your computer is working OK. Make sure the applications you depend on are still working. Try out the applications from Apple that were updated with the OS. If you have trouble, restore your backup and go back to the old OS version.
  4. Recover
    • Wait for Spotlight to finish indexing (may take several hours). Performance will suck till it finishes.
    • Turn on Time Machine and start your backup.
    • You don't have to repair disk permissions with Disk Utility any more. In fact, you can't; the option is gone.
    • Restart the computer. Often this speeds things up.

Post Install Tasks

Once you are satisfied that your computer works acceptably, and you are going to stay on Big Sur, you can make some adjustments.


You will probably want to set up per-user customizations, such as your desktop background and screensaver. After each new OS generation this is something of an adventure; functions get renamed and moved around.

Security issues

Catalina reorganizes your startup disk so that MacOS is stored on a read-only file system partition. This means that transitioning to Big Sur has to move things around, and that going back to Mojave or earlier will be difficult.

There are additional security checks done by Gatekeeper. macOS will insist that programs are "notarized" in order to run them.

Some kinds of security certificates are no longer accepted. These are the ones using SHA-1, which is deprecated.


Re-Installing Programming Tools

If you use your computer for programming, you'll need to re-install your tools, which may have release dependent parts. The order presented here worked for me.

  1. The default shell is now zsh, which appears to have an incredible number of features and options. (This appears to be a result of GPL licensing issues on newer versions of bash.) You can still use the old bash until you figure out how to change over, and if your scripts have a first line of #!/bin/bash you will still get bash. Here is an exhaustive comparison of shells. For example, zsh doesn't split parameter expansions by default, bash has a help builtin, there is no read -p prompt in zsh -- use read cmd\?prompt, arrays start on 1 (not 0) in zsh, commandonly search for external commands in zsh, there is no (simple) equivalent to ${foo^.} (uppercase only first character) in zsh.
  2. (check this) In Terminal, type the command java. If you don't have Java 8 installed, this action will bring up a dialog box: click More Info to bring up the Oracle JDK installation page in a web browser, and trigger the installation of the Java 8 JDK from Oracle over the Internet. (check this) Java is needed for Eclipse and for other Mac applications, such as OpenOffice, and VPN clients such as Cisco. Java is not dangerous, if you use it to run code you trust: using it to run web page animations has had some problems.
  3. Install the full Xcode package using the App Store, and then install the Xcode command line tools from the Xcode menu. This will take a long time, about an hour. (Just using xcode-select won't work for some complex installs, which look for system header files installed by Xcode.)
  4. MacPorts: see my instructions for MacPorts. Basically the procedure is to list your ports and uninstall them before upgrade, install the OS, reinstall MacPorts, and reinstall your ports. MacPorts will install new versions of Perl, Python, or Ruby required by ports: set PERL5LIB correctly or installs will fail with messages about variants. (In future operating system versions, this is where to install Perl, Python, and Ruby.)
  5. MySQL: Version 8.0.24 is supplied by Oracle for Big Sur and Catalina. See the instructions for installing MySQL. If you dumped your database, reload it with mysql < db.sql. MySQL has to be installed before you can install DBD::mysql with CPAN.
  6. MaxMind: If you use Perl module MaxMind::DB::Reader::XS, you must download and install libmaxminddb from before installing the MaxMind module with CPAN. (I had trouble doing this. The instructions say to do ./configure but no such file is provided. Luckily the file left over from Sierra still works.) Install any other libraries that are used by Perl modules at this point.
  7. Perl/CPAN: If you use Perl and Perl modules, install them. Perl 5.26.2 is installed by MacPorts as it installs various modules. ==== check this, might be 5.28.1 ==== See the instructions for installing CPAN for a list of modules I use. This is the time to install Python and Ruby libraries also.
  8. Apache web server:
    • Apache 2.4.34 is provided with Big Sur, but is not automatically started and there is no System Preferences interface to enable it. You can buy products like VirtualHostX or MAMP, or use Terminal commands.
    • The Big Sur install will not carry over your old Apache customizations. diff /etc/apache2/httpd.conf against your saved copy and edit as necessary.
    • Start Apache using the terminal command sudo launchctl load -w /System/Library/LaunchDaemons/org.apache.httpd.plist. The -w means make it permanent across restarts. (I got a fussy message when I did this, but the web server was running.)
    • PHP 7.3.8 is shipped with Big Sur but disabled in httpd.conf. You can enable it by uncommenting LoadModule php7_module libexec/apache2/ and restarting Apache. I sometimes enable PHP in order to debug programs that will be deployed in safe environments on other computers. If you enable it, be aware of the risks of making PHP available on the Internet from your Mac, and track and install security updates.
  9. Screen saver: if you patched the duration of a screen saver slide, as I did, you will have to reapply the patch. You will have to disable SIP to do this, and then re-enable it after patching.

Big Sur Observations

to be updated

Microsoft Office

to be updated


I no longer use Adobe products.

New Features and Changes


to be updated


to be updated


New Features:

Login Screen

to be updated

Screen Saver

Because the arrow keys no longer allow you to control the screen saver (as of Mojave),

Bugs and Surprises in Big Sur

to be updated


Mail can now block all mail from specific senders, automatically deleting any incoming messages from them.

iTunes Replacement

to be updated


to be updated


to be updated. Mention zsh

Notifications and Photos

to be updated


to be updated

About This Mac

to be updated


to be updated


to be updated


to be updated

Removed Features

to be updated

Planning for the next version

The next macOS version, Monterey, will released in Fall 2021. A beta is available already.

Keep a list of the software and devices you use and depend on, so you can check that they are supported.

Home | FAQ © 2010-2021, Tom Van Vleck updated 2021-07-21 10:54