Chosen Solution
I was given an old MacBook Pro (early 2015, 13”, retina) with a corrupted hard drive which I was unable to revive. I bought the Transcend Jetdrive 850 SSD to replace it. Using a friend’s MacBook, I downloaded the Mojave installer into a USB key. However, when I launch the MacBook into recovery mode (Option + R), it won’t recognise the new SSD, either in Disk Utility or when using diskutil list in the Terminal. It still recognises the old corrupted SSD so it’s not the connector that is broken, and I’ve been given a replacement Transcend drive that still isn’t recognised, so it’s unlikely that both new SSD’s have shipped faulty. Unfortunately I don’t have immediate access to another Mac, and don’t have an enclosure for an NVMe SSD. If need be I can get access to a Mac, and am willing to buy an enclosure if it is likely to be the solution. Would connecting the SSD externally to another Mac using an enclosure (and then formatting it if recognised) be a likely solution? Could another reason be that I don’t know what OS was running on the Macbook before the original SSD got corrupted, and it needs new drivers to detect the new SSD? If so, what would be a way to work around that? Thanks!
Well you’re warm ;-} Your systems firmware (EFI) was not updated to support the newer APFS file system and the installer / recovery files have an expired certificate If you’ve got an old macOS install image, it will probably stop working today You’ll need to jump back to MacOS Sierra and you’ll need to get this OS image in Step 4 here: How to upgrade to macOS Sierra Using another Mac follow this guide to create an OS installer USB thumb drive How to create a bootable macOS Sierra installer drive Once you’ve got the drive formatted and setup under GUID / HFS+ you can then upgrade to Mojave with GUID / APFS file system. You’ll need this image file though How to upgrade to macOS Mojave again the file link is in Step 4.
