MacOS Monterey Won’t Install Onto Macs with Non-Apple HDD

Her really you aren’t correct that the brand of ssd doesn’t matter, but Apple seems to be rejecting the update because the computer firmware is not updated. A catch 22 problem.

how did you upgrade your system firmware to allow for the upgrade?

It is the problem! It only occurs if you have a third party drive installed.

I have exactly the same problem, and this is nothing difficult for Apple to resolve for the next release. This is just another Apple restrictive practice, which fortunately MS do not engage in. Having migrated totally to Apple after a lifetime with MS, I shall vote with my feet and move back to MS.

Wow! OWC has been loyal third party manufacturer for decades now even before the days when Apple was hanging on for its dear life. You'd think they would show some gratitude and respect by recognizing their drives during the firmware update process, or at the very least, clue them in on a better solution than swapping drives.

No, it isn't. I've had all kinds of drives installed in my Macs purchased separately. I've had various types of third party drives. None of them have ever prevented me from installing any OS I want.

Apple does not manufacture their own drives. They buy them from a third party, just like every other computer maker does. There's no such thing as an "Apple" drive.

The only exception I know of where you need a specific drive is Apple gets some drives custom made for their laptops. If replaced with a non-exact replacement, the cooling fans run on high nonstop because a small thermal sensor is missing from that drive and the OS thinks the drive is running hot, even when it isn't.

so if that isn’t the issue, what is? Monterrey still won’t load as an upgrade.

i have replaced my original hard drive with an OWC SSD on my Mac Pro 2010 and never had a problem upgrading to the next OS that could be installed. Running OSX Mojave was no problem with my new graphics card. And now with open Utility I am running OSX Big Sur.

That all sounds very logical, except it would depend on how old your computer is, and what model. For a 2018 Mini or newer, and really, pretty much all newer laptops and iMacs, the SSD is soldered to the logic board. There's no way to replace or remove the original drive to begin with.

That makes no sense as I have never purchased any drives from Apple, as if those were the only ones that would work in a Mac. I bought run of mill hard drives from Amazon or OWC and put them in a 2010 Mac Pro, or in an external case. All worked the same as any other drive. All SSDs I've purchased came from OWC. Sometimes already in one of their external housings, other times as a drive only and put it on my own housing. Same thing. Nothing Apple about them, and they all work. I can install any OS on them I want.

If what you say is true (and I know you have the expertise to know this), what's in Apple's drive firmware that's so important?

I've got Monterey installed and running flawlessly on one Samsung EVO 860 (internal late 2015 21.5" iMac), one OWC Aura Pro NT (internal drive on late 2016 MacBook Pro 13") and five Samsung T7s as standby drives in lieu of bootable clones fro our five Macs.

All installations went without problems and all are performing as expected. My experience is the brand SSD makes no difference.

That's why I said "My experience", YMMV.

As to a system firmware upgrade, I did nothing. I just attached the SSDs and proceeded as usual. I've had zero problems with any of the drives or Macs ... all five of them

The drive isn't the problem. Monterey is trying to install a firmware update to your iMac, which it can't because it doesn't qualify to run that OS.

Where can I get an Apple drive for my MacBook Pro mid 2015? I tossed my old one.