Download macOS Big Sur. If you're using macOS Mojave or later, get macOS Big Sur via Software Update: Choose Apple menu System Preferences, then click Software Update. Or use this link to open the macOS Big Sur page on the App Store: Get macOS Big Sur. Then click the Get button or iCloud download icon. 3 Steps to Reinstall macOS Big Sur or Catalina without Losing Data. We all save tons of data on our Mac, so when we decide to reinstall macOS Big Sur/Catalina, the top concern always goes to “will I lost everything if I reinstall macOS”.

• Catalina: More changes. There are lots of smaller improvements in Big Sur. Photos gets a refreshed interface, improved retouch tool that is driven by a machine-learning algorithm, new editing options, and better Memories with new soundtracks. The Music and Podcasts apps, which replaced iTunes in Catalina, have new For You.
• Below you'll find instructions for using Docker (Docker-OSX) to run a macOS (Catalina or Big Sur) base recovery image, install and run macOS (with the option of setting a custom resolution; with no options specified it uses 1920x1080). There are also instructions for removing the container.
• In this video, I’m going to explain how to downgrade from macOS Big Sur.Download CleanMyMac X to clean your Mac before you back up your data:https://bit.ly/3.

After many months of fine-tuning, Apple finally released macOS 11.0 Big Sur in November 2020. The major features (like the new Safari) have been announced much earlier and fans, as well as haters, had their say. Still, many users ask themselves, whether macOS Big Sur is worth it. So, let’s take a look at macOS Big Sur and macOS Catalina to find out what improvements it brings.

Big Sur has more demanding system requirements than Catalina and you may also need to free up space on your Mac to install it. CleanMyMac X can help with both of those by running scripts to optimize your Mac’s performance and highlighting files you can safely remove, potentially freeing up several gigabytes of space.

Big Sur vs. Catalina: user interface

In Big Sur, Apple redesigned the interface for its built-in apps like Photos and Mail. They now have sidebars that stretch the full height of the window and toolbars with sleeker, simplified icons.

Finder windows now have more curved corners and plain white (or dark) backgrounds on title bars and toolbars.

The Dock has also been redesigned. The corners of the Dock are more rounded, and app icons are all the same shape, giving it a tidier look. Icons also have enhanced shading and shadows that make them appear less flat than in Catalina.

Control Center appears on the Mac for the first time in Big Sur, accessible from a menu bar item. Like on iOS, it allows you to control things like Wi-Fi, Bluetooth, and AirDrop and volume and display brightness. You can drag your favorite items to the menu bar.

The Notification Center in Big Sur now puts notifications and widgets in a single view and it groups notifications by app. Some notifications are interactive, so, for example, you can play a podcast episode directly from Notification Center.

Sheets, the alerts that dropdown from the top of windows to request you take action, now scale to the center of the window, are accompanied by the rest of the screen dimming, but also are less obtrusive than previously.

Symbols for things like Share or Undo are now more consistent, all taken from one library of symbols.

macOS Big Sur vs. macOS Catalina: Safari

Apple says that the update to Safari in Big Sur is the biggest ever. It boosts performance, reduces energy consumption, and adds features to improve privacy. Big Sur Safari also allows you to customize your homepage by adding a background image. Then you can add elements like your reading list, iCloud tabs, and even a Privacy Report.

Tabs have been re-designed to allow you to see more of them at once, and hovering over a tab brings up a preview of the page. Safari can also translate pages between seven languages with one click, tell you if any of your saved passwords have been compromised, and show a report of all the cross-site trackers it is blocking to protect your privacy.

macOS Catalina vs. Big Sur: Messages

Messages in Big Sur gets lots of new features, many of them similar to those that have been in other messaging apps for years, but better late than never. In Big Sur Messages, you can pin up to nine conversations to the top of the message list, reply directly to messages in group conversations and “mention” others, and add an image to identify a conversation.

Messages also allow you to search for and add GIFs and trending images, create and add Memoji on the Mac, and search messages more quickly. Early reports from Big Sur users suggest that searching in Big Sur is much faster than in Catalina and that Messages on the Mac is finally on a par with the iOS version, which is great news.

macOS Big Sur vs Catalina: Maps

Maps is another app that has lagged behind its iOS version. However, in Big Sur, that looks to have changed. Maps now allows you to create guides to locations, as well as access guides created by others.

It also has cycling routes, charging points for electric vehicles, and indoor maps for some locations. And then there’s Look Around, Apple’s version of Google Street View, also in Big Sur Maps. Look Around allows you to get a street-level 3D view of locations. Apple hasn’t yet said which areas will be covered, but it’s likely to be very limited initially.

Big Sur vs. Catalina: App Store

Privacy has been a key theme of the last couple of macOS releases, and Big Sur is no different. As well as the privacy report in Safari, Apple now displays privacy information in the App Store. For each app, types of data collected by the app are split into three categories: data used to track you, data linked to you, and data not linked to you. That makes it very easy to see at a glance how a specific app is using, say, your location data, or your financial information.

Big Sur vs. Catalina: More changes

There are lots of smaller improvements in Big Sur. Photos gets a refreshed interface, improved retouch tool that is driven by a machine-learning algorithm, new editing options, and better Memories with new soundtracks.

Clean Install Big Sur From Catalina

• The Music and Podcasts apps, which replaced iTunes in Catalina, have new For You recommendations and new layouts. Podcasts also gets a Listen Now feature and a more focused Up Next to make it easier to find the next episode of the podcasts you’re listening to. There’s a new section to help you find the latest episodes of podcasts you subscribe to, and there are hand-picked episode recommendations. The startup chime that disappeared from some Macs has been restored. And system sounds have been updated to make them easier on the ear. Apparently, this has been done using snippets of the original sounds. So the new sounds should be familiar, yet more pleasing to listen to.
• Spotlight has been beefed up in Big Sur and is now faster than ever. And it presents results in a more streamlined format to make them easier to browse. It also has Quick Look features that allow you to preview the whole of a document or web page by scrolling through it. It has the same markup tools that were added to the Finder in Catalina, allowing you to do things like rotating an image, cropping it, or signing a PDF, all within Spotlight. Spotlight also powers Find in Safari, Keynote, Pages, and other Apple apps.
• Siri can now answer questions you ask by searching the web then telling you what it has found.
• Voice memos, introduced in Catalina, gets the ability to organize recordings in folders and smart folders. It can also remove background noise automatically and room reverb with a click. And you can mark recordings as favorites.
• The weather widget in Notification Center gets some of the features Apple acquired when it bought Dark Sky. In the US, it will display a minute-by-minute chart showing the intensity of rain or snow over the coming hour. In the US, Europe, Japan, Canada, and Australia, it will display government alerts about severe weather. And all users will be able to see when the weather will be much warmer, colder, or wetter the next day.

How to improve your Mac’s performance with Big Sur

1. Download CleanMyMac X if you haven’t done so already, and follow the instructions to install it.
2. Launch it from your Applications folder.
3. Choose the Optimization module and click View All Items.
4. Review each category and check the boxes next to those you want to remove.
5. Press Perform.
6. If an item can’t be removed independently of its host app, click ‘Enabled’ next to its name to disable it.

There are many differences between the macOS Big Sur and Catalina. Some of the most obvious ones are the addition of Control Center, the change to Notifications, and the improvements in Safari. But there are many other changes too. Before you upgrade, it’s worth running CleanMyMac X to optimize the performance of your Mac and clear space.

macOS Big Sur vs. Catalina: The sumup

I’ll admit it: I’ve gotten a little used to working at smaller companies, where there’s no monitoring of company computers, and it’s the Wild West as far as what you can install on them.

That’s no longer the case for me. I now work at Auth0, a company with a headcount that’s quickly approaching 800, with unicorn status and Series F funding, and it’s in the security industry. Naturally, there’s a full-fledged security team that monitors company-issued computers.

In my excitement to take the new version of macOS — Big Sur — out for a spin, I’d forgotten that the Security team hasn’t yet approved it for use. They very quickly (and I should add, nicely) contacted me and let me know that I needed to reinstall macOS Catalina as soon as possible.

There are other reasons why you might need to go back to Catalina after installing Big Sur:

• It’s still very new, and very new versions of operating systems always have some set of issues, whose effects can run the gamut from mildly annoying to catastrophic. If you can’t afford to lose time dealing with these issues, you should wait for the updates.
• There are reports that the current version can “brick” MacBook Pros from the 2013 / 2014 era. This isn’t a problem if you’re keeping your old 2013 / 2014 machine around as a backup, but more serious if you’re still using it as your main computer (and yes, a 2013 / 2014 Mac is still a perfectly good machine, even for development work).
• If you’re a DJ or music producer, Big Sur currently has compatibility problems with some of the hardware and software. If you want to keep DJing, producing, or mixing on your Mac, stay on Catalina for a little bit.

For the benefit of any who need to downgrade, here’s a step-by-step guide to reinstalling Catalina after you’ve installed Big Sur. You’ll need a USB key and the better part of an afternoon.

Step 1: The preliminaries

1a: Start downloading the Catalina installer from the App store

The first thing you’ll need is the macOS Catalina installer.

It’ll take up around 9 gigabytes of space on your hard drive, and the App Store will put in your Applications folder.

Once it’s completely downloaded from the App Store, the installer will start automatically. When this happens, close the installer. You’ll make use of it later.

The installer will take some time to download. Apple’s servers will be busier than usual, as many users are downloading Big Sur and other upgrades.

1b: Back up your files!

In the process of reinstalling Catalina, you’ll need to completely erase your Mac’s hard drive. If you have any files that you can’t live without, this is the time to back them up.

I didn’t have to worry about this, since:

• All my work product is either code (which lives on GitHub) or content (which lives on GitHub or Google Docs), and
• I’ve been at Auth0 less than a month, and between onboarding and offsites, there just hasn’t been that much of a chance for me to accumulate that many files on my hard drive!

1c: Get a nice fast USB key that stores at least 16 GB

The process will involve booting your Mac from a USB key containing the macOS Catalina installer, so you’ll need a key with enough space. An 8 GB USB key won’t be big enough. Because digital storage is all about powers of 2, the next size up will be 16 GB.

I strongly recommend that you use a USB 3 key, especially one with read speeds of 300 megabits/second or better, such as the Samsung Fit Plus. Doing so will greatly speed up the process. Don’t use a USB key that you got as conference swag — it may have the space, but more often than not, they tend to be slow, because they’re cheap.

If the USB key contains files that you want to keep, back them up. You’re going to erase the key in the next step.

Step 2: Make a bootable USB key containing the macOS Catalina installer

2a: Format the USB key

Plug the USB key into your Mac, then launch Disk Utility.

Select the USB key in Disk Utility’s left column, then click the Erase button:

You’ll be presented with this dialog box:

Enter MyVolume into the Name field, and for Format, select Mac OS Extended (Journaled). Click the Erase button. This will format the USB key with the volume name of MyVolume.

2b: Install the macOS Catalina installer onto the USB key

In Step 1a, you downloaded the macOS Catalina installer and closed it after it started automatically. In this step, you’ll transfer it to your freshly-formatted USB key.

Open a terminal window and paste the following command into it:

(The command above assumes that you gave the USB key the volume name MyVolume.)

Once you’ve provided sudo with your password, you’ll be asked if you want to erase the USB key. Entering Y in response will start the process of making the USB key a bootable drive and copying the macOS Catalina installer onto it:

The Erasing disk process will be relatively quick, but the Copying to disk process may take a while. This is where using a nice, fast USB 3 key will pay off.

Be patient and let it get to 100%, and wait for the Install media now available message to appear and the command line prompt to return.

2c: If your Mac is from 2018 or later, set it up to boot from external media

Check the year of your Mac’s manufacture by selecting About This Mac under the Apple menu:

• If your Mac year is 2017 or earlier, you don’t need to follow the rest of this step. Proceed to Step 3.
• If your Mac’s year is 2018 or later, you’ll need to change its security settings to allow it to boot from an external drive.

Here’s how you change the security settings:

1. Restart your Mac and hold down the ⌘ and R keys when you see the Apple logo. This puts the computer into recovery mode, which provides many setup options.
2. In the menu bar, select Utilities, and then select Startup Security Utility from the list that appears.
3. The Startup Security Utility window will appear:
   1. Under the Secure Boot section, select Medium Security. This will allow you to install Catalina without having to connect to a network.
   2. Under the External Boot section, select Allow booting from external media. This will allow you to install Catalina from a USB key or disk drive.

Step 3: Install macOS Catalina

Restart your Mac, and hold down the Option key while it restarts. Your Mac will present you with a choice of startup disks.

Choose the USB key. Your Mac will boot up and you’ll be presented with the macOS Catalina installer screen:

Go ahead and install Catalina.

Once Catalina is installed, you can proceed reinstalling your other software.

Once that’s complete:

• If your Mac’s year is 2017 or earlier, you’re done installing Catalina. You can now go about reinstalling your software and restoring your backed up files.
• If your Mac’s year is 2018 or later, you’ll need to restore its original security settings. The process is described in Step 4, below.

Step 4: If your Mac is from 2018 or later, restore the original security settings

If your Mac is from 2018 or later, follow these steps to restore the original security settings once Catalina has been installed:

How To Downgrade Big Sur To Catalina

1. Restart your Mac and hold down the ⌘ and R keys when you see the Apple logo. This puts the computer into recovery mode, which provides many setup options.
2. In the menu bar, select Utilities, and then select Startup Security Utility from the list that appears.
3. The Startup Security Utility window will appear:
   1. Under the Secure Boot section, select Full Security.
   2. Under the External Boot section, select Disallow booting from external media.