Installing Mojave - circle with /

Meant High Sierra 10.13.5

I have the same issue : I tried to install 10.14 on an external GDrive SSD and got the same crossed circle after a long installation process. I also tried to reboot, and the install always ends on the same black screen with this warning sign.

Here too. MacBook Pro 2016 with external USB 3.1 SSD.

Maybe this Beta version does not support external USB Startup volumes, yet.

That's what I thought in the first place, but there is no such mention in the 10.14 release notes.

You should enable the verbose starting mode, FreeBSD dmesg like. It would give you useful info.

Boot with CMD+V pressed. If you want it activated every time you boot (as I do), it’s not trivial but can be done in five minutes.

1. You have to disable CSR NVRAM: reboot on 10.13 recovery slice, open Terminal, type "csr disable nvram". Ignore the warning.

2. Reboot on your usual 10.13 partition.

3. In Terminal, type: "sudo nvram boot-args=-v"

That should set you in verbose boot mode by default.

If you reboot then, you should get more info on what's wrong.

Thanks Vingt-Cent,

I've just tried it. So, the last message that is displayed before the warning sign appears is approximately : "AppleUSBHostPort :: disconnect :: persistent enumeration failures". In fact, there is another line that is written just before the failure screen, but this last one makes the text over the screen totally unreadable.

I launch the install on a MacBook Pro 1016 on an external SSD drive that is probably an USB-C one...

You could capture what's going on onscreen with a smartphone and examine the footage image by image.

I’m not sure what the message exactly means. Enumeration usually refers to the computer probing the USB bus for any device attached. If that probing fails for whatever reason, that may explain why the boot process aborts: it can’t find the disk it’s been booting from (booting is driven by the EFI, i.e. the firmware).

Another thing you can try is booting in single user mode: CMD + S at boot and see what happens.

I tried single-user mode and the last messages were USB-related, something about invalid packet size - wMaxPacketSize

After a video analysis of the screen just before the failure sign appears in verbose mode, the message is: "still waiting for root device".

Same message in single user mode.

That's it: the root disk cannot be mounted, that’s why the installation fails. No root, no system, of course.

I wonder if that’s a bug or a deliberate behavior. Maybe you'd get a better answer if you filed a bug report?

FYI, USB works in this version. I mounted an APFS-formatted external disk this morning, it seemed to work fine.

> That's it: the root disk cannot be mounted, that’s why the installation fails. No root, no system, of course.

That makes sense... But the boot process seems to have already started, and the external drive should already be accessible.

> I wonder if that’s a bug or a deliberate behavior.

There is no mention in the release notes, that Mojave beta installation on an external drive is not allowed.

> Maybe you'd get a better answer if you filed a bug report?

The bug reports rarely (never?) conduce to an explaination 😁

Thanks again Ving-Cent...

As I briefly mentioned, intial boot relies on the EFI USB drivers. Those might work. Then when the kernel is loaded, the EFI drivers are killed and the kernel's take over. That's why, if your phone is connected to your Mac, you can see it powered at start, then the power fails, and turns up again a few seconds later.

I wish I had read that (comment) before I tried installing on an external SSD. I installed beta onto an internal SSD and it seemed to do ok. I tried on an external SSD and it failed at various points with a circle and 2 slashes that form a nice X --> ⓧ

I was never able to get it to work on a touchbar MBP -- but I was able to get the system to boot up using the external SSD on an iMac 5K. It's probably normal v1 beta -- but the performance is a bit choppy (slow internet, slow bluetooth), etc.

I'll do more tests with various other MACs to see what happens.

Scott

Has anyone been able to install on an external USB attached drive? I can't tell from this response if they did or not.