Big Sur a Migration tip
This tip is from a series of tips of upgrading Mac OS X 10.7 Lion, 10.8 Mountain Lion, 10.9 Mavericks, 10.10 Yosemite,10.11 El Capitan, 10.12 Sierra ,10.13 High Sierra, 10.14 Mojave, 10.15 Catalina, 11 Big Sur, 12.0 Monterey, and 13.0 Ventura, and 14.0 Sonoma client release.
Server edition forum is over here:
macOS Server - Apple Community
November 12, 2020 Apple released Big Sur. Simultaneously, the first Apple Silicon Macs were released, and then will not run an older Mac OS.
September 21, 2023, Apple released Safari 16.6.1, after releasing Big Sur 11.7.10 on September 11, 2023 via Apple menu -> System Preferences -> Software Update. With the release of Sonoma, on September 26, 2023, Safari no longer is updated on Big Sur, and other browsers may offer better security for Big Sur.
Backup your data before installing anything.
Before upgrading, don't do so, in order to optimize your speed. Frequently an optimizer will slow you down, and it won't stop from slowing you down by upgrading your system. Your first step is to make sure your system is running optimally before upgrading. Upgrades are there for feature enhancements and new features. If you have already been trying optimizers, read what I have to say about removing them:
Amended comments to MacKeeper tip - Apple Community
Use this guide to free up space.
Go to Apple menu -> System Preferences -> Date and Time and select the closest time server to set your time, and do so. Download based on manual time may fail, especially on older systems where the system time is not set right.
11.7.10 is available on software update only (current downloads from the App Store take you to 11.6 immediately). The website does not have any version of Big Sur available for download directly. It is either the App Store for the Upgrade, or the Software Update for the Update. It addresses various additional security issues as documented here. It is the last release of Big Sur, on September 11, 2023.
11.2.2 (an older update no longer available) addresses issues with third party USB hubs and Big Sur.
Apple has a link of prior installers, including Big Sur on: How to download and install macOS - Apple Support
Be forewarned, Macs with solid state drives will be updated in formatting to APFS with 10.13 or later (this is discussed later in the tip, but bears repeating). This means if you need to downgrade the machine, you will need to erase the partition with the older HFS extended GUID to use the older systems. Regardless of which direction you go, backup your data first. This is only for Macs older than September 25, 2017.
macOS Big Sur is compatible with these computers - Apple Support says these are the requirements.
MacBook Air (2013 or later) [Machine ID 6,1 shipped with 10.8.4, has to be upgraded to Mavericks 10.9 first
if you saved it in your App Store, or 10.12 from the App Store & have 35 GB free after the upgrade first before installing Big Sur.]
MacBook (2015 or later) [Machine ID 8,1 shipped with 10.10.2]
MacBook Pro (Late 2013 or later) [Machine 11,1 shipped with 10.9]
Mac mini (2014 or later) [Machine ID 7,1 shipped 10.9]
iMac (2014 or later) [Machine ID 14,4 shipped with 10.9.3]
iMac Pro (2017 or later) [Machine ID 1,1 shipped with 10.13.2]
Mac Pro (2013 or later) [Machine ID 9,1 shipped with 10.9.1]
Some of the older models may need special directions to apply the upgrade:
Note: the Macs with only 128 GB of storage will barely have enough room to install just the operating system and a few applications and photos and music. If you are using such a Mac, you will want some form of external storage for primary use, and at least a secondary if not a tertiary drive for backing up. 1024 GB = 1 TB
Added bracketed information to supplement info from Apple's page above. To further identify your computer, see this tip.
You must Backup your data before installing to at least two distinct places. Software installs may result in incompatible software or drivers, and a wipe or separate partition install of the computer will be needed to restore the prior operating system if you aren't ready.
10.12 or later users must have 35 GB free to install before installing Big Sur on an existing system. Big Sur will run without issue on a 2015 MacBook Pro with 18.5 GB free on a 40 GB partition. and 8 GB of RAM based on the author's testing. Based on author's testing, you do not want less than 15% free of your partition to avoid swap files from reducing space rapidly on any Mac OS X. This may be arbitrary, but has been consistent. Other authors don't recommend running Big Sur on a Mac with only 128 GB of SSD space built-in. A lot is dependent on if the system was not overly filled to begin with.
https://roaringapps.com/ is an excellent source for compatibility, however, make sure reports are post dated the November 12, 2020 release date. A different listing with similar info can be found here:
The other thing to keep in mind with Big Sur is Rosetta 2. A new environment released for Apple's new chip replacing the Intel CPU. This allows running of certain Intel only compatible applications on Apple's M1 and later CPUs. Sadly support for Microsoft Windows is left to third party virtualization companies with Apple's new chips. Apple's T1 and T2 chips only affect the security and should not be confused for the M series chip.
No 32 bit application or driver is compatible with Big Sur or the prior OS, Catalina. If you find after the fact your applications are not compatible, you can partition a hard drive to install an older OS (note the third option for booting to install older systems), if your Mac is older than Catalina's release date. Further information on its compatibility with applications can be determined through the System Report (a.k.a. System Profiler) information from Apple menu (the menu in the upper left corner with the Apple logo)-> About This Mac. Only those applications that say "Yes" under 64-bit (Intel) are compatible. You can even click on the column header to sort 64-bit (Intel) to group just the applications you need to update for Catalina. Notice how in the image below the arrow on the far right with the 64-bit (Intel) is pointed up. This brings the non-64-bit applications up first.
If About This Mac is slow, you can use
https://www.stclairsoft.com/Go64/index.html
To determine what software is native.
New Macs released on or after this date most likely will require Big Sur for installation if prior releases are any indication.
Big Sur Mac OS 11.0 was released November 12th, 2020 The download from the Mac App is over 12 GB.
A 2 Mbs= 256kBs DSL connection will take 2000 seconds per GB or about 24000 seconds, 400 minutes or 3.5 hours. 100 Mbps cable connection will take 8 minutes. Longer times to be expected during the prime daylight hours nearest the download location.
Note, if only have 128 GB for your computer, that means you'll need to keep 20 GB+12 GB = 32 GB free for the operating system. That is based on the arbitrary amount of data being free, being 15% where many techs have found to work best with Macs. 1024 GB = 1 TB. That's just the time to get the installer off the internet. The installer itself can take a couple hours to run if there is 35 GB of contiguous space available. It will not work at all if there is less on certain systems.
The following peripheral manufacturers have updated their websites with Big Sur links:
Epson - link to help page, individual drivers will be by device
HP - by model
Lexmark - latest drivers listed are for 10.14. Check individual model.
Additional feedback is on this thread for Lexmark MX517.
Samsung -HP discussion indicates PCL 6 drivers are compatible with at least some Samsung printers.
M1 printing issues - third party reference for dealing with older printers on M1 computers.
11.0 Big Sur Printer support as of Big Sur initial release from Apple. Link added June 8, 2021.
New M1 Macs released in 2020 have additional compatibility differences that need to be observed as well. Be sure to check with your software developer if they require any routines in their software that won't work in M1.
Big Sur RAW Camera support file is covered in this article.
Additional information will be added as it becomes available.