Problem slow boot with apfs on ssd external

Same problem here:

iMac 21" later 2017 8GB RAM

SSD + USB 3.1/C case

Boot times:

High Sierra = 25 seconds after power on, Apple logo shows fast

Mojave (APFS) = About 3 ~ 4 minutes, big delay on Apple logo; after appear, Mojave starts fast.

Yeah .. sigh I bought a sandisk extreme SSD so I can enjoy atleast a fast boot time and here comes Mojave.. What is going on in Apple.. first they made it so hard to open the system an install it yourself and now this.

If only mine was just 4 minutes. 90 minutes is about what I get with a MacPro (2013) and Mojave. It was the same with High Sierra. And i just replaced my samsung 860evo (in an inatec case) with a sandisk extreme because i was convinced it was the samsung going bad... waste of £200 there.

Thanks apple... no it was nothing. Really... nothing...

Needless to say the chances of me buying another mac ever again are pretty bloody slim... testing of any description seems to have been thrown out completely in the last few years with all apple products

Suggestion from apple is that the conversion to apfs is not the correct way to move to apfs. You need to do an erase and format as apfs... obviously that requires moving your data.

initial testing here suggests this is correct but i am still moving data around to test once i have my data back on my drives...

I took a brand new Samsung T5 SSD and formatted as APFS, then used Carbon Copy Cloner to migrate everything from the internal boot volume. Merely having it connected to my iMac results in a 1-2 minute delay in between the startup chime and it actually starting to boot.

So it would seem that at least with this issue there is no difference between having the installer convert your drive to APFS versus formatting it APFS.

@PCzzz, I'm glad you resolved it for you, but I don't see why ejecting the drive would make a difference. The drive basically gets ejected when you reboot or shut down the computer.

Based on what you said, I booted to the old, internal drive, installed the T5 software and it found a firmware update since the last time I had done this. I installed the firmware, ejected the drive just for the heck of it, and then rebooted. The problem seemed to be gone! The computer chimed, and I could see it accessing the T5 twice, then it quickly found the T5 as a startup volume and booted up. However, when I shut down and powered it up later, the startup delay was back.

I did file a bug report with Apple on this; we'll see what they say.

You are right: after my first euphorie of a quick boot (and telling everybody about it), the slow boot came back just as you describe. I am sorry and sad. It is definitively a problem caused by the password-security FirmWare in the T5, which does its work even if there is no password activated (but the firmware always is ...?.). Actually: Apple has done some good work in realising a boot-up at-all. Well, it is still totally unacceptable that neither Apple nor Samsung gives us a solution or even a hint, how to install a T5 as a bootable ssd with reasonable boot-up-time (while the screen is completely black!). This way we cannot advice anybody to buy a Samsung T5 external disk when they want to boot from it !

That's too bad, I'm sorry to hear that.

I don't think this issue is specific to the T5, actually. A friend of mine duplicated it for me with his Sandisk drive in a USB enclosure with the same results. Prior to that, I had contacted Samsung and a Support person told me they are aware of the issue and that it happens with other manufacturer's drives as well.

You don't even need to have Mojave installed on the external drive, it just needs to be formatted as APFS.

Yes, I can confirm this: after much a-do during installing the Mojave 10.14.3-update, the start-up is now super-quick: 4 seconds black screen and 1 minute with the apple logo on screen. Very good, Apple!

Considering all the security (EFI) aspects that played probably a role, this is a neat solving of the unacceptable long start-up time. Especially unacceptable because it showed a completely black-screen all the time for 5 minutes ...! That is long, the first time, I can tell you.

But: I am afraid that the update problems will return with every new update, because every restart during the update, it could not find a startup-disk, displaying a blinking ?-Folder and not responding to ANYTHING except a long OFF press. And an Option+ON start to choose the startup-disk. And choosing "OS-Installer" (not the T5) from the list of startup disks. And the same Option+ON again until I could just only choose my external T5 disk.

But I know how to handle it, now. Just happy and a bit exhausted.

Yep, fixed also for me using a Crucial SSD (MX500 500Gb) as external boot device.

Apple Logo is coming up within 15 sec i.o. 4 minutes with release 10.14.2 , boot completed and login window appears in less than 1 min.

Thanks Apple :)

When Mojave was released I updated from Sierra to HS. I was sorry I did that when I ran into all the messy APFS business. However, by staying one OS behind the current release, there was plenty of accurate advice about the APFS problems. Of course, if everybody stayed one OS behind...

Same here, exactly the same problem on a external SSD.

not found a solution yet

I have exactly the same problem. In High Sierra, there was the option to keep HFS+ but this option is gone with Mojave 😟

I fixed it but its not pretty...

i just took my imac apart and installed the ssd internally.

no delay at all, everything is instant.