Apple’s latest macOS is named after the coastal region of “Big Sur” along the Central Coast of California. “Big Sur” is designed to to support Macs with ARM-based processors known as Apple silicon. As of today, the latest production release is version 11.2.

(Update is availabe at the end of this blog for installing Big Sur 11.4 Beta 1)

Once again, Apple discontinued support for older Mac devices to run this “Big Sur” operating system.

“Big Sur” Mac Hardware Minimum Requirements
MacBook (2015 or later)
MacBook Air (2013 or later)
MacBook Pro (Late 2013 or later)
Mac mini (2014 or later)
iMac (2014 or later)
iMac Pro (2017 or later)
Mac Pro (2013 or later)

My 27 inch iMac late 2013 missed out on this macOS update. I suspect, although it’s 100% capable of running this “Big Sur,” if it has the notorious Fusion Drive as a system drive it struggles running the new macOS with smooth operation.

You should avoid Mac computers or Windows PCs that have “Fusion Drive” inside as you are only asking for trouble.

Big thanks to genius BenSova releasing Patched Sur for Mac users having unsupprted Mac computers running this “Big Sur”

You can get Patched Sur program from this link.

To create an installable patched “Big Sur” USB thumb drive, you need to have a macOS Catalina (10.15.*) environment. (I created the Catalina environment with an external USB connected SSD drive with the bare minimum configuration for this exercise.)

Please always test with an external usb connected SSD drive (conventional hard drive is too slow to operate) to run patched “Big Sur”.

You will be inundated with a number of postings, but as a start, you can take a look at (MacRumors) macOS 11 Big Sur on Unsupported Macs Thread.

If you require video assistance, Mr. Macintosh YouTube channel is the place to go. (This is an initial video guide using BenSova’s Patched Sur ver 0.4.0 – already outdated but good place to start)  Please take a look at Mr. Macingosh YouTube video using Pached Sur ver 0.1.1. Patched Sur version is now all new 0.2.0 – here is the quick video link BenSova himslef posted.

As a result, I now have “Big Sur” 11.2 on my iMac 27 inch late 2013 and so far absolutely no issues (performance wise, much better than running Catalina – I hate to say but Catalina was a disastrous operating system and I did not like it at all).

Take a look at the following image for proof.

Big Sur running on unsupprted iMac



MacOS Big Sur is now updated to ver 11.2.1.  I applied this update downloading full installation *.pkg file created updated USB stick base installation media.  As far as I tested with my iMac 27 inch late 2013, BenSova’s Patched Sur ver 0.4 beta was the only version worked.  (Most recent version is now 0.7 beta).  Much of process involved for this update for installing USB connected SSD drive – not straight forward process at all.  Finally, my iMac 27 inch 2013 is now running Big Sur ver 11.2.1.

Big Sur running on unsupported iMac ver 11.2.1

Big Sur ver 11.2.1


Apple released macOS Big Sur 11.2.2 on 25/02/21. macOS Big Sur 11.2.2 targeted bug and security fixes including a serious bug with third-party accessories that in the worst cases could damage newer models of MacBook Pro and MacBook Air.

I had to wait genius BenSova’s new release Patched Sur ver 0.10 beta to create a full installer USB stick under my environment using unsupported iMac 27 inch late 2013.

Moreover, I could not create a full installer USB stick under an external SSD disk with bare bone Catalina ver 10.15.7 using any BenSova’s Patched Sur release ver 0.04 beta to 0.10 beta (encountered number of errors creating a USB installer stick). I had to use Big Sur ver 11.21 installed in an external SSD environment to create an external full installer USB stick.

Best to download a full installer package from the following link first.

Big Sur ver 11.2.2 full package

(Please copy paste the above link in a new Tab.  Otherwise, download will not start)

Ever since the release of macOS Big Sur, Apple decided to change Timemachine file format to APFS.  Almost all Mac users use conventional hard drive to store Timemachine backup.  Do not know why Apple has chosen APFS for Timemachine backup.  It does not add any benefit at all.  Aslo, I realised everytime you apply big update (like ver 11.1 to 11.2), previously stored Timemachine backup becomes useless and waste of space.

Big Sur ver 11.2.2

Big Sur ver 11.2.2 on unsupprted iMac


Apple has released macOS 11.2.3 on 8/3/21 and the build comes with important security updates that Apple is recommending for all users.

(It means macOS Big Sur still has a long way to go for stable functionality)

Genius BenSova released Patched Sur ver 0.1.1 beta and I tried to create a full installer USB stick under my environment (bare bone Catalina 10.15.7 on an external SSD using unsupported iMac 27 inch late 2013.


1. I have no plan to install macOS Big Sur on my iMac 27inch late 2017 internal PCIe M.2 SSD as I’m happy with installed macOS Mojave (10.14.6).

2. Under my bare bone Catalina 10.15.7 external SSD disk, I could no longer create workable proper USB stick install media.

a. Used brand new USB 3 16GB stick

b. Ran BenSova’s Patched Sur ver 0.1.1

c. First run – encountered the following error

Error 1×250
Message: “Password:Erasing disk: 0%… 10%… 20%… 30%… 100%
Warning: Failed to copy product icon to volume icon path
IA app name cookie write failed
The bless of the installer disk failed.”
Output: “Copying to disk: 0%… 100%
Making disk bootable…”

d. Shutdown and restarted Catalina, used Disk Utility to erase USB3 16GB stick naming xxx

e. Ran 2nd time – it appeared successfully creating installable USB stick, however, it named install media as “Install macOS Big Sur beta”.

f. Shutdown and restarted iMac only connecting internal PCIe m.2 SSD and USB stick named “Install macOS Big Sur beta”

(if you connect previously created working Big Sur external SSD at the same time, only Mojave disk will show up when you restart iMac whilst pressing Alt key)

g. Connect Big Sur external SSD – it will show up

h. Ran installer targeting to update from ver 11.2.2 to 11.2.3

i. Windows pops up – corrupted media

If the above is a general occurrence, it means there is no way for a Mac user who has Big Sur unsupported Mac computer and plan to use BenSova’s Patched Sur and creating install USB media for Big Sur installation using Catalina environment (not yet created USB stick installer).

What I’ve done

1. Used Big Sur ver 11.2.2 external connected SSD disk.

2. Download Big Sur ver 11.2.3 full installer package.

macOS Big Sur 11.2.3 (20D91) – 071-14766 – Added 2021-03-08 18:04:29

(If you would like to download the above full package, please copy paste above link in a new tab. Otherwise, download will not start)

3. Ran BenSova’s Patched Sur ver 0.1.1.

4. Used the above full package as a source.

5. Successfully created USB 3 16GB stick installer (labelled as Install macOS Big Sur).

6. Shutdown the iMac.

7. Detached target disk Big Sur.

8. Started iMac connecting only internal PCIe m.2 SSD (Mojave) and USB3 installer disk whilst pressing alt key.

9. Attached target disk Big Sur ver 11.2.2 (it will appear on the screen).

10. Started USB base installer.

11. Ver 11.2.3.installer successfully started and began writing to the target disk.

12. In the middle of upgrade, iMac restarted and came back with Mojave login screen.

13. Shutdown iMac.

14. Detached target Big Sur external SSD disk.

15. Started iMac connecting only internal PCIe m.2 SSD (Mojave) and USB3 installer disk whilst pressing alt key again.

16. Attached the target Big Sur external SSD and it will show up. You will see macOS Installer partition and Mojave-Data partiton.

17. Choose macOS Installer – continued for upgrade installation.

18. It restarted again during the upgrade.

19. Do the same as above.

20. It restarted again but this time if you attach the target Big Sur external SSD – you will see only one partition named Big Sur.

21. Detach USB stick and choose Big Sur disk to start.

22. After a while, it successfully started Big Sur ver 11.2.3.

The above is very tedious process but I found so far that would be the only solution for me to continue with Big Sur updates.

This is my experience only and I’m not testing any other Big Sur unsupported Mac computers.

Big Sur ver 11.2.3 on unsupported iMac

Big Sur ver 11.2.3 on unsupported iMac


Create “Install macOS Big Sur” USB disk image using unqualified CCC (Carbon Copy Cloner ver as macOS built in Disk Utility cannot create USB disk image (*.dmg file).

1. Use CCC ver (prompt comes up saying CCC is not qualified on this version of macOS (Big Sur)).

2. Warning comes up when creating “Install macOS Big Sur.sparsebundle CCC disk image file – not bootable” saved to an external disk.

CCC Warning Disk will not be bootable

CCC Warning Disk will not be bootable


Disk Image File of Install macOS Big Sur USB created by CCC

Disk Image File of Install macOS Big Sur USB created by CCC

3. Detach the original Install macOS Big Sur USB disk

4. Click the image file “macOS Big Sur.sparsebundle” and it will mount “Install macOS Big Sur” disk image file on the Desktop

5. Simply clone the image file to GPT formatted USB (Warning again comes up saying it will not be bootable). For the sake of this exercise, I used a disk name as “xxx”.

6. Cloning finishes.

CCC 5.1.19 Screen Shot

CCC 5.1.19 Screen Shot

7. Use the cloned USB stick – works without any issues.

Super Duper!

As reported on the net, Super Duper (latest version is 3.31),  it can do nothing delaing with macOS Big Sur.  Not too sure when update is coming around.

Super Duper Faied

Super Duper Failed

Price to Pay

My experiment continues.

Tried to restore the Big Sur ver 11.23 Timemachine backup to a new external connected SSD disk. It appears the only way possible to restore the Timemachine backup is to go through Migration Assistant. This means that Direct Restore is not possible. Not too sure if this is happening because I’m using an external connected disk or not. Most likely, it’s a price to pay using Big Sur unsuported iMac.

Direct Timemachine Restore not Possible

Direct Timemachine Restore not Possible


Genius BenSova’s new release Patched Sur ver 0.1.2 beta.  It says “Patched Sur v0.1.2 beta fixes a bug that came with disabling AMFI. TL;DR”.  I did not comment on Patched Sur 0.11 beta where applying update from inside of Big Sur now possible (it did not work).  Wait to see when Apple releases macOS Big Sur ver 11.3.


Genius BenSova’s new release Patched Sur ver 0.1.2 beta works fine within Big Sur environment for inline update without creating a bootable USB Disk.

  1. Start iMac with Install macOS Big Sur (ver 11.23) USB Disk
  2. Run terminal and input command “csrutil disable” (Disable System Integrity Protection – SIP)
  3. Shutdown
  4. Start iMac with an external connected SSD (Big Sur 11.23)
  5. Run Patched Sur program exracted from Post-Install-App.dmg (Copy to Application folder)
  6. Update iMac – it will download full package of Big Sur 11.3 beta 3 (Public Beta)
  7. Follow the instruciton
  8. During the update reboot a few times, just keep track of install media (start iMac with the install media)
  9. Finally, it will start updated Big Sur 11.3 beta 3
Big Sur 11.3 Publinc Bata 3 running on unsupported iMac

Big Sur 11.3 Publinc Bata 3 running on unsupported iMac

This is a very good news for me.  Most likely, I can keep updating Big Sur on my unsupported iMac in the future without creating install USB media. (Full install package will be downloaded for each update, so if required, I can create install USB media afterwards)

Note: The above inline update from Big Sur ver 11.23 to 11.3 (Public Beta 3) did not requrie tedious updating process described in my update on 11/3/21.  I did not have to detach and attach target disk to be recognised.

After the above experiment, my external bare bone Catalina ver 10.15.7 would not start up at all.  Most likely I have to do NVRAM reset for the Catalina disk to start.  As my internal PCIe M.2 SSD Mojave 10.14.6 and external SSD Big Sur are working fine, I’ve decided to leave it as is.  As such, I can not experiment Catalina environment USB installation disk creation any longer.


Apple has released BiG Sur 11.3 beta up to beta 8 and also released 11.3 RC (Release candidate) a few days ago. I’ve decided not to test these beta updates and release candidate but rather wait for the final version of 11.3.

Instead, I’ve decided to chase 11.4 beta

Apple has just released Big Sur 11.4 beta 1 for developers.

(If you would like to download the above full package, please copy paste the above link in a new tab. Otherwise, download will not start – the above link may not last long)

Although there are many patch programs available for unsupported Macs to run BiG Sur, I’ve decided to only follow BenSova’s Patched Sur ver 0.1.2 beta for a moment. (Patched Sur is now updated to all new ver 0.2.0 – ever better!)

1. Download Big Sur 11.4 beta 1 from the above link (InstallAssistant.pkg) and placed in the download folder of the iMac 27 in 2013 running Big Sur 11.3 beta 3. (Note: You do not have to download full package file to do the update as Patched Sur can download in the background.  But it’s always nice to pre-download the full package in your hand to save updating time)

Donloaded Big Sur 11.4 Beta1

Donloaded Big Sur 11.4 Beta1

2. Start Ben Sova’s Patched Suit Program in the Applications folder.

3. Choose “Update macOS” and use the browse function to locate the pkg file.

4. Proceed with updates.

5. Encounter the following errors:

Error 1×1
Message: “Password:”
Output: “installer: Error – the package path specified was invalid: ‘/Users/<user>/.patched-sur/InstallAssistant.pkg’.”

I had to copy the InstallAssistant.pkg, but the folder cannot be found usual way.  If you know the locaiton of the folder you can use Shift + Command +. to unhide the hidden folders.  If you do not know the hidden folder locaiton, you use an application like Find Any File.

Downloaded Big Sur 11.4 Beta 1 has to be copied here

Downloaded Big Sur 11.4 Beta 1 has to be copied here

6. Run the Patch Sur program again – very smooth installation flow and did not encounter any issues. (iMac restarted a few times to complete the update).

After update is done, InstallAssistant.pkg will disappear from .patched-sur hidden folder.

Hidden Fodler

Hidden Folder – InstallAssistant.pkg will dissapper

Conclusion: Ben Sova’s Patched Sur program is still great (maybe the best provided your Mac can run macOS Catalina natively).

Big Sur 11.4 Beta1

Big Sur 11.4 Beta1 running on unsupported iMac


I applied Big Sur 11.3 fianl release on my unsupported iMac 2013 27 inch using genius BenSova’s new release Patched Sur Beta 2.0.1 (New release is now available for Beta 2.1.0. )

Big Sur 11.3 Final running on unsupported iMac

Big Sur 11.3 Final running on unsupported iMac

Carbon Copy Cloner is now back to support Big Sur

Carbon Copy Cloner (CCC) ver  now supports Big Sur (I tested on my Intel chip unsupported iMac 27 inch 2013 – Sorry, I have no way to test it on M1 Apple chip Mac and I do not have any plan to purchase M1 chip Mac device at a moment).  Very good news.

Carbon Copy Cloner Supports Big Sur Intel Chip

Carbon Copy Cloner Supports Big Sur Intel Chip


If you need help for Mac computers  (Sydney CBD, Sydney North Shore – particularly in Chatswood, Roseville, Lindfield, Killara, Gordon, Pymble, Turramurra, Wahroonga, Warrawee, Hornsby, Macquarie Park and St Ives area) please contact Harry 0417 424 909.  Or refer to our Service page.

Your comments are welcome (subject to moderation).  Nickname is allowed for comment posting, however, you must provide a valid e-mail address (will not to be displayed).  If you fill out Website box, website address will be linked on your name appeared on the comment.  As regard to the treatment of your e-mail address, please refer to ACE PRIVACY POLICY.