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

Mid 2015 MacBook Pro.

That one you can indeed replace the drive.

Well, let me go to the landfill and find that original failing “apple” drive, hit it with a hammer and hope it works when I re-install it. What total BS.

Nothing is attached to my MacBook Pro 2015. That’s not the issue.

I wish I knew Apple's reason for restricting the macOS Monterey firmware updater from working with third party SSDs. It certainly seems intentional since they would have to go out of their way to check for an internal Apple SSD. If I had to guess, Apple believes the third party SSDs are not reliable in some way and would interrupt the system firmware update and brick the Mac. macOS has been known to brick Macs for years even with Apple OEM drives, but at least Apple used to provide firmware restoration CDs to recover from a bad firmware update and more recently with the T2 DFU "Restore" option, but many Macs from 2012-2017 have no way to recover corrupt firmware.

Keep in mind that macOS installers from 10.13+ also will not install even to an external drive unless the internal drive is properly erased for use with macOS. This is something I personal experienced and discovered. Like with the Monterey installer, once the Mac's system firmware is updated, then the macOS 10.13+ installer will most likely install to an external drive even if the internal drive has been removed (I never had time to test installing macOS 10.13+ again after the system firmware was updated to confirm). My guess for restricting the system firmware update to the internal drive is probably the risk of a USB drive being more likely to be disconnected midway through the system firmware update and bricking the computer. Apple started making these changes beginning with the macOS 10.13 High Sierra installer. Only macOS Monterey seems to have the additional restriction to requiring an Apple OEM SSD.

Also, most of the Apple PCIe SSDs I believe are actually identified as "Apple SSD" even if the rest of the SSD's firmware is from the SSD manufacturer (Samsung, Toshiba, SanDisk, etc.).

Also, most of the Apple PCIe SSDs I believe are actually identified as "Apple SSD" even if the rest of the SSD's firmware is from the SSD manufacturer (Samsung, Toshiba, SanDisk, etc.).

Yup, that's what System Information reports on the internal SSD of my 2018 Mini, too:

APPLE SSD AP1024M

But like you said, that despite the fact Apple doesn't actually make the SSD. And then there's my external SSDs (I have three of them). All were purchased from OWC. The oldest is a slower 3G drive I had in the 2010 Mac Pro, and moved it to one of OWC's external housings when I sold the 2010. It is very noticeable how much slower that drive is compared to the 6G drives in the other two USB-C housings.

Which now makes me wonder; since I have no issue installing Mojave and forward to any of these third party SSDs, does OWC silently add some sort of Apple firmware to the drives so they're compatible? There also isn't much of a clue reported from the drives. Such as this:

Device Name: Elite Pro mini

Media Name: AppleAPFSMedia

Medium Type: SSD

Hmm.