Slow boot time after update to Mojave - External SSD

Sorry JDW1, but I have to agree to TravellingKiwi. Of course, there are many, many reasons for lots of kinds of boot delays and all of them are very annoying. But in this thread, we're only dealing with the type of boot delay that is caused by the combination of APFS and external SSDs (USB and - partially - TB). If we broaden this subject to other reasons for boot delays, we are losing the focus on this specific problem and its possible solutions.

I manage an office with eight iMacs of varying vintages (from late 2012 through current models). All of them have been upgraded with external SSD boot drives (Transcend or Samsung T5s). NONE had an issue booting in High Sierra. ALL of them have the lengthy boot in Mojave. I'm hoping Apple finds the fix for this soon!

You can agree with all manner of traveling fruit, but the fact remains that this thread reads how it reads and such applies to my situation as well. I am using APFS on an external SSD. There is no "broadening" of the subject going on here.

Like I said, I await the next update to MacOS X Mojave to see if it has any positive impact at all.

...I'm really counting on this!!!! AFAIK, 10.14.3 will be released by the end of January; beginning of February the latest, so hopes are high that our boot delay sufferings come to an end very soon!!!

But yes, can anyone actually confirm that the USB boot delays are still gone in beta 4 ?

Oh wow so happy. Finally getting the performance I was hoping for when I created a DIY fusion drive using an external SSD to put new life into my late 2013 iMac. Startup has gone from 2 minutes plus to 20 seconds. Feel like I have a new computer!

Thats strange. Mine takes about 5 seconds max before the Apple Logo comes up. I have 3 External USB 3 HD, 1 BR/DVD Burner/Reader, Scanner attached to my iMac. They power up first and spin up then the iMac Apple logo comes up less that 5 seconds. Then the boot up process is super fast as before with the External SSD. Perhaps a combo update is what you need or make sure you select the SSD as the Startup Disk again?

Instead of doing the Mac OS Update Only from the control panel, which only applies added updates, Apple has the combination update which combines all. In some cases for some users (including me) this has helped resolved strange behavior after a standard update. If my Mac is acting weird after the standard update, I use the combo to stabilize it. Lately the normal updates has been good, except for this boot delay, that I haven't had the need to do a combo in awhile. Some people like to do combo updates only. https://support.apple.com/downloads

Well, I've just gone backwards.

My MacPro - With OS on the INTERNAL drive and an externally connected SSD with APFS and used as a home directory has gone from 1 minute to 3 minutes 48 boot time.

Most of the extra BEFORE the pre-boot kernel is loaded (I boot with verbose mode so I can see what it's doing). For slightly over 3 minutes from the chime that all is fine I just have a blank screen while my MacPro contemplates how to take over the universe by boring me to death

You could fix that by combining the two drives to create a DIY fusion drive as I did. Then the OS decides what content goes on the HDD (internal) and the SSD (external) invisibly to you. It works like a dream now the Mojave update has fixed the bug that was causing this particular setup to 'go slow'. My five year old iMac feels like a brand new machine. It's a bit tricky to do - there are lots of online guides to doing it though. The main thing is you have to copy all your content, reformat the drives, then restore all your content. Is a bit anxiety-making in the process but I'm so glad I did it.

Definitely an improvement on my 2015 iMac with USB 3.0 Samsung EVO 860, however there's still about 14 seconds between the chime and the Apple logo, so still not perfect. Still, at least it's usable again now.

We... Installed the Combo update version. Same thing as the regular 10.14.3 update.

Takes about 25~27 seconds to show the apple logo. And more 35 seconds to get fully started and ready to use.

Come on... It is a 2017 27"!

Should be better this boot.

I'm using my Samsung T5 1TB connected to the USB-C port.

https://www.samsung.com/us/computing/memory-storage/portable-solid-state-drives/portable-ssd-t5-1tb-mu-pa1t0b-am/

With my internal FusionDrive the apple logo appears in about 5~6 seconds and more 25~30 seconds to get fully started and ready to use.

Now it's much better than those 3min to start, but still not solved my problem yet.

Here's the situation after updating my external SanDisk 2TB USB SSD to 10.14.3:

Takes 35 seconds from the point where I click Restart in the Startup Disk control panel inside System Preferences to where I first see the Apple logo. I could hear the standard volume boot chime during that restart. It then took about a minute until it rebooted again, this time with a softer boot chime (akin to what you hear during firmware updates), and it finally booted to the Desktop, taking a total 2 min. 35 seconds (measured from the point at which I clicked the Restart button). Had there not be a stupid dual reboot sequence, it likely would have taken only 1 minute 35 seconds total.

This is all the reason why I have Mojave only on an external drive as a test. I am still running rock solid High Sierra on everything else. In my eyes, Mojave is still very much a bag of hurt.

MacOS 10.14.3 Update.

From almost 2,5~3 minutes to:

- 27 seconds from pressing the power button to Apple logo and another 26 seconds to Login screen.

I repeated a few times and it's the same.

I can say that is better now.

Personally, I can live with this.

But there is room for improvements.

Before 10.14.3, I was on 2-3 minutes between chime and Apple logo too, sometimes even longer. Now I'm back to about 7 seconds between chime and apple, just as it was before Mojave/APFS. Finally - THANK YOU Apple for fixing this utterly annoying bug at last!

I don't know why it's taking that long for your setup. Perhaps Apple needs to tweak the update more in the future for external USB-C port setups? Mine is 1TB Sandisk on external USB3 enclosure. From Chime to Logo is around 5-7 seconds. Depending on my externals drives sleeping or already spinning. Then the boot process is 25 seconds or so.