Monterey Installer app fails preparing installation

Use the original SSD.

I confirm the following worked great for me on my 2015 MacBook Pro 15".

1. Installed original SSD.
2. Installed fresh copy of Monterey via the USB stick onto the original SSD (it rebooted a bunch of times, indicating a firmware update).
3. Put the new SSD back in.
4. Booted off USB stick and upgraded to Monterey without a hitch.

It sucks if you don't have your original SSD but maybe you can get a cheap one off of the interwebs. Doesn't have to be big. Likely doesn't even have to be the same one that came with your unit. Most likely just *any* genuine Apple SSD.

Good luck.

Just a bit of feedback. I have an OWC SSD in my Mac Pro, and fortunately still had the original Apple SSD in a USB housing. I contacted OWC to see if they could help. They confirmed that re-installing the original Apple SSD and installing Monterey would fix the problem, as installing the new OS updates some sort of BIOS in the Mac Pro which then allows the OWC SSD to be upgraded to Monterey.

It was a bit of a pain to do. But quite straightforward. I made sure my Mac had a good Backup then created a bootable USB Stick with the Monterey Installer (instructions on Apple's website). I reinstalled the Apple SSD in my Mac Pro and upgraded it to Monterey by starting up from the bootable USB stick. I then replaced the OWC SSD in my Mac, and did a fresh install of Monterey from the bootable USB Stick (thought it was a good opportunity to do a fresh install rather than an upgrade), before re-syncronizing my iCloud content and re-installing applications and the like.

All this took about an afternoon of messing around, but definitely worth it as I'm now running the latest OS (which I hope will upgrade more easily in the future) and my Mac Pro feels much snappier than it did before the OS upgrade.

To continue....The other thing I did after turning off the firewall when the initial two attempts of downloading and installing Monterey through software update failed: I downloaded macOS Monterey from the App Store. Took over an hour l. So far so good. I have agreed to terms, entered my admin password and selected my hard drive for the installation.

As I write this, installation is at midpoint and went from 15 minutes remaining to 1 minute very quickly (you can hear fans running at this point). It sat on 1 minute remaining for a while, perhaps three minutes, restarted, proceeded with an Apple logo and progress bar, reaching about 20%, restarted again, and continued until completion. Restarted again, progress bar running again from about 20% fairly quickly and restarted again at about 75% completion. Progress bar is running again. Near mid point heard a notification beep, keyboard lit up, touchpad cursor arrow appeared and it now says 9 minutes remaining, once again with a progress bar. Down to 2 minutes remaining, although dragging out a bit. One minute, less than a minute remaining, all good. Purple desktop appeared with prompt for my password.

Checks iCloud status then shows macOS Monterey 12.0.1

(Note) noticeably speedier response.

Turned Firewall back on, restarted, all good.

I upgraded from latest version of Big Sur on a mid 2019 (July) 13" Touchbar MacBook Pro, faster processor and graphics model.

What SSD is installed? Is it an Apple SSD?

A while ago I replace the internal Apple SSD with an NVMe drive with adapter in my late 2013 MP. I successfully updated to Big Sur with no problem but could not update to Monterey. Could not even install Monterey on a blank external drive. Then I Googled and it appeared that an Apple internal SSD has to be installed in order to update the firmware and OS boot loader. I installed the original Apple SSD which had Mojave and updated successfully to Monterey. I then booted from my Big Sur NVMe SSD and successfully updated to Monterey. I am typing this from that OS now.

It’s not so much a hardware issue rather than a firmware issue. Once the firmware is installed, which can only be done with an OEM SSD for some reason, Monterey can be installed on the 3rd party SSD. In the future if a different firmware is needed to install an new OS version the OEM SSD will probably have to be put back in and this process done all over.

This fixed my issue trying to install on a 2013 MacPro with an upgraded (OWC) SSD. Reinstalled original drive - had to make some space - installed 12.0.1 then reverted to OWC SSD and installed OK.

I ran into this problem too. Like the others described here, the workaround is to install an original Apple SSD. I documented my approach here:

http://www.schwie.com/brad/?p=1116

I also confirm that I had to reinstall the original SSD on a mid 2015 MBP. I downloaded Monterey on an OWC Aurax1 several times. Always hung up with restart and kept getting an error to redownload. When I put the original Apple SSD in (thank goodness I still had it), I updated to Monterey. Reopened MBP and reinstalled to the OWC Aura x1, and the Monterey picked up instantly with start up.

I think Apple may be in violation of some sort of legal ruling similar to when you buy a car and using other than original parts. I believe it's called the Magnuson-Moss Warranty Act. I guess we will see what happens. Maybe OWC, Samsung, Crucial and other drive manufacturers will approach Apple on this or may the California State Attorney General or FTC. Who knows. At least there is a solution, if you can get an Apple drive.

I would like to update you that my laptop resuscitated in Apple Store with the DFU solution. I am not sure about the problem but many people went to this Apple Store today for the same problem.

There seems to be some belief that ONLY systems with after-market drives fail to install. This is INCORRECT. My 2017 Model 18,3 iMac, with all original equipment fails to install with the "... can't install required firmware..." popup. I've also tried to install from USB. Finally, I installed the OS onto an external SSD using a 2015 MacBook Pro (on which Monterey successfully installed), and plugged that into the iMac. I rebooted the iMac using the SSD into Monterey, and then attempted to install using the Monterey installer onto the iMac internal drive. Unfortunately, the installer successfully overwrote the Big Sur 11.6.1 OS on the internal drive to OS 12.0.1, but failed to complete the installation (no encrypted OS snapshot) and will no longer boot from the internal drive at all. Because the Big Sur installer finds OS 12 already installed, it is unable to overwrite and reinstall Big Sur on the internal drive. The iMac runs Monterey fine from the SSD, but will no longer boot from the internal drive at all. I migrated my user profile to the SSD, and am still able to access my data, and use the system that way. Bottom line, the Monterey 12.0.1 installer clearly has some pretty fundamental flaws, does not function with even baseline Apple configuration, and should presumably have not been released. Beta testing that failed to reveal even this most basic shortcoming was clearly inadequate. I guess I'll wait a couple months to see if Apple bothers to release a patch. Failing that, the only way to install Monterey on my 2017 Model 18,3 iMac system is to use the external SSD, migrate what programs I can to that, and do a complete clean install on the internal drive(s). That's cumbersome, and pretty inconvenient.

@georgeapplefan @joshuapinter

I have a couple of questions about this internal SSD thing. I have a Mac Pro 2013 and replaced the Apple with the OWC Aura 2TB SSD a couple of years ago. I do still have my original Apple SSD and it is in a little enclosure that I can attach via USB.

1. Can I use the Apple SSD as the boot disc and update that way?
2. Or what about restart using Ctrl+Shift+R and install Monetary that way?

Thanks for the input!

That's what I am doing. You have to create a bootable Monterey USB installation drive. Do a search for a video on how to do that. You'll need a 16GB USB drive (or bigger) do this. I actually am using an old spare 60GB hard drive in a USB enclosure for that. Then boot into the boot menu by holding down the Option key while it reboots. Then load the installer and have it install it on your original SSD in the USB enclosure. Then when it's done it you should be able to unplug that drive and then install Monterey on your new SSD.

Well this thread is helpful but incomplete. As of this past week, OWC is offering a "rental" Apple Branded SSD if you do not have the original as in an upgraded 2013-2019 MacPro bought directly from OWC. However, getting Monterey onto even that SSD can be a challenge. Go to https://support.apple.com › en-us › HT201372

This gives excellent instruction on installing Monterey on a bootable disk (any drive) via terminal command.

Type "sudo /Applications/Install\ macOS\ Monterey.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume" and the terminal will install the Monterey Install image onto a bootable disk. Now you can install onto the apple drive, replace with the upgraded OWC disk and install Monterey there.

There appear to be two instances of installer failure included in this thread. One appears to be, more or less, "solved," in that those with aftermarket internal drives as replacements for failed hardware or upgrades need to go through some gymnastics to fool the installer into seeing Apple hardware to allow the firmware upgrade and subsequent OS install to run. Then there is MY problem, and at least two others in this thread, where the installer fails to run on relatively new (2017, in my case), factory OEM hardware. In my case, the "... firmware update..." popup ALSO shows up. This seems to be a smaller group, so far. Should I start another thread?