"Could not create a preboot volume for APFS install" on MBP 2018

[Yoms]

Hi,

I'm totally unable to use my MBP 2018 with T2 chip. I received it today from a retail non-Apple store. It came with High Sierra.

1) I couldn't update to Mojave form MAS. After an hour or so I had downloaded only a few MB. I checked my Internet connexion on Speedtest.net and it resulted in a "socket error" at the end of the test. But, on my older MBP everything is running fine and normally (SpeedTest included). I tried again 3-4x times to update via MAS, rebooting the MBP 2018 eacht time, but same result.

2) A bit concerned, I decided to go for a clean install of Mojave using Option + Cmd + R. I first erased the disk via DiskUtility and then started the Internet installation, but at end of installation I got the message mentioned in the thread title. All solutions seem to point to reverting back to HFS, but that's no longer an option with the newer MBP.

3) I decided to go for USB install. I downloaded Mojave from MAS on the older MBP + createinstallmedia, but installation was a no go: the T2 secure enclave is configured to refuse install from external source and stated that I had to reboot in Option + Cmd + R to modify the security parameters (OK, fair enough).

4) I did that, except that when I was invited to provide my macOS pwd, it stated that there was no admin accountconfigured. I mean WTF?! I thought the T2 chip would have stored my very first macOS pwd.

Since the disk has been formatted, I'm left with no other option.

What's wrong? What did I do wrong?

Help would be appreciated as I literally can no longer use this brand new MBP.

Thanks! (A LOT!!!)

 

[Uncle Freddie]

Interesting problem. Did you actually boot off the USB Mojave installer? For that, you would need to hold down Option during boot and choose the USB drive.

 

[Yoms]

Interesting problem. Did you actually boot off the USB Mojave installer? For that, you would need to hold down Option during boot and choose the USB drive.

Yes I did at step 3. Well, tried. But then I have a message about not being authorized for security reason.
[doublepost=1539150409][/doublepost]There's also another problem. When I try to do the Internet restoration, it doesn't work when the MBP is connected yo my xDSL home network. After having accepted the terms and selected the destination drive, I don't DL one single percent.

But, if I do the same while connecting the MBP to my iPhone and share the connexion through my mobile carrier, I can DL. But at the end, I have the aforementioned issue about APFS.

 

[Yoms]

OK, for some unknown reason I repeated the Internet restoration and it worked. I really don't why why the AFPS didn't show up again, but I won't complain.

I don't like this weird behavior. It reminds a Windows PC. That's exactly why I switched to Apple years ago. Also, I haven't tried to boot from USB install drive again just to see if my password works in T2 enclave or if it still states that there's no account defined.


That said, I don't understand this T2 thing. It refuses to re-install from an external disk for security reason in case my computer is stolen. OK, fine. But it accepts to restore from Internet without asking any pwd. I mean, why this is more secure?