MacOS Mojave: An error occurred while verifying firmware [duplicate]

I have a Mid 2011 iMac currently running MacOS 10.12 Sierra. It’s not my main machine, but I would like to install 10.13 on it.

Updating starts smoothly enough, but when it comes to restarting, I get the following message:

macOS could not be installed on your computer An error occurred while verifying firmware.

I understand that my Mac is on the edge, but I read that any machine which supports 10.12 will also support 10.13

The iMac is running from an external SSD, due to a problem with the logic board, so I know that I have some problems. The iMac no longer boots from the internal drive (or recognises the DVD), but still works otherwise.

However, the problems don’t seem to be invove the actual firmware, and the iMac is happily running 10.12.

What does this message mean, and can it be resolved?

Solution 1:

Apple has introduced a new file system APFS in High Sierra. The easy fix is to verify your backup and then erase the volume and run the installer against a blank / erased main storage drive.

• https://support.apple.com/en-us/HT204904

Because the APFS requires support from a new version firmware, your mac's firmware will have to be updated to the latest version during the installation of High Sierra.

After the first restart, the installer prepares the latest version firmware which suitable for your mac model onto EFI system partition of your main disk with bless command. Then restart automatically and trigger the firmware upgrade process. (marked as point A)

After the upgrade process (regardless success or fail), the installer continues. It double checks the version of firmware to make sure it was updated successfully in previous process (namely point A). As a result, the installer find out that your firmware is NOT a latest version still. Hence, it reports "An error occurred while verifying firmware". Yes, it is what you saw on the screen.

The root cause of the failure at point A, in your case, is no internal drive in main bay. The firmware upgrade process only recognize the ESP (EFI System Partition) of primary internal drive. That means the upgrade process was interrupted.

So, you might have to get the primary SATA port work and connect your disk to it. It's said that, most of time, it is the hard drive cable which is out of order, instead of the chipset. If that is the case, it probably can be fixed within $20 to get a replacement. And that was my case. :)

Solution 2:

I had the same issue trying to install High Sierra on my late 2011 MacBook Pro, in which I'd replaced its mechanical HDD with an SSD. The fix was to download the latest version of the High Sierra installer from the App Store and run that - it is version 13.1.05 at the time of writing. Make sure you delete any existing installer you might have first.

This version ran without issue first time, updating the computer's firmware and installing High Sierra.

According to anecdotal comments online, it seems that Apple is installing a firmware upgrade and older versions of the High Sierra installer only worked with specific drive configurations. In my case, I expect the firmware checker was expecting a HDD in this machine when it's now an SSD.

Solution 3:

Had the same problem on a MacBook Pro 17” (Mid-2010). Turns out it was the aftermarket SSD I had installed pretty much as soon as I bought it. Luckily I kept the original hard drive around, and after trying the newest installer and rebooting into safe mode several times without any joy, I just took a screwdriver and put the old HDD back in temporarily (there are good guides on ifixit.com). The installation with the original HDD completed without any problems, including the firmware update. Afterward, I put the SSD back in and installed Hugh Sierra without any problems - as the firmware update had already been completed, there no longer seemed to be the system check that had tripped me up previously.

Many thanks for your helpful answers. Incidentally, I also have a late 2009 iMac where the original hard drive has been swapped out (drive failure - not even the same manufacturer) and an SSD occupies the optical drive bay. In contrast to my MacBook Pro, the update finished without problems on the iMac. That fits with the issue being related to the primary SATA port.