I have an iMac late 2015 which I have upgraded to a SATA 2TB drive and configured to a Fusion drive so I could upgrade to Big Sur safely. Will I be able to upgrade to macOS Monterey without issues?? How many more macOS's should I get out of my iMac now that it is a Fusion drive?
iMac 27″, macOS 11.7
The Age of this computer will Govern what newer version of macOS it will Qualify to install. Use About this Mac from the Apple Icon on Desktop - the required Information will be there.
With the above information in-hand - follow this How to get old versions of macOS and verify what version this computer Qualifies to install. For Best results use Safari to commence the download as Others may not work.
Safari will open a redirect and open the Apple Store where the download can commence.
Computer Qualifying for macOS 13 Ventura
Computer Qualify for the Monterey upgrade
Notation on After Market Internal or External Drive and Specifically on Monterey.
The Monterey Installer contains an EFI Boot ROM within the Installer.
During the Installation process - it will verify if an Apple Original Drives is used on the computer
If it does not find this drive, the Installer will Baulk and may even present some type of Error Message
Background, The EFI BooT ROM needs to Flash the Computer ( not the drive ).
Until that specific condition is met - Monterey will be unavailable for this computer
The workaround would to exchange the After Market Drive with a Apple Original and install Monterey on that drive.
Then reverse the exchange replacing with the After Market Drive and run the installer to that drive.
It should work as the EFI Boot ROM has flashed the Computer
EDITED
The Age of this computer will Govern what newer version of macOS it will Qualify to install. Use About this Mac from the Apple Icon on Desktop - the required Information will be there.
With the above information in-hand - follow this How to get old versions of macOS and verify what version this computer Qualifies to install. For Best results use Safari to commence the download as Others may not work.
Safari will open a redirect and open the Apple Store where the download can commence.
Computer Qualifying for macOS 13 Ventura
Computer Qualify for the Monterey upgrade
Notation on After Market Internal or External Drive and Specifically on Monterey.
The Monterey Installer contains an EFI Boot ROM within the Installer.
During the Installation process - it will verify if an Apple Original Drives is used on the computer
If it does not find this drive, the Installer will Baulk and may even present some type of Error Message
Background, The EFI BooT ROM needs to Flash the Computer ( not the drive ).
Until that specific condition is met - Monterey will be unavailable for this computer
The workaround would to exchange the After Market Drive with a Apple Original and install Monterey on that drive.
Then reverse the exchange replacing with the After Market Drive and run the installer to that drive.
It should work as the EFI Boot ROM has flashed the Computer
EDITED
FWIW, Monterey is the last version of macOS you can run on a Late 2015 iMac.
You may use this command-line method here to get+try Monterey 12.6.1 installer first,
as that version is less buggy than the current (Dec 2022, Jan 2023) last 12.6.2 version.
pls make TimeMachine backup before upgrade, so that you can go back to it, if you notice/face too many issues.
Can I upgrade to macOS Monterey?
