Problem slow boot with apfs on ssd external

The only fix I found is a thunderbolt enclosure for the SSD. Got mine today and boot time is normal, now.
The problem occurs before the Apple logo shows up. It took up to 4 minutes before the logo shows. After that boot time was about 30-40 seconds. With the thunderbolt enclosure it is between 10 to 30 seconds until Apple logo and another 10 to 20 seconds boot time. There have to be some changes with the USB boot loader, because it takes the same amount of time, if I press the ALT key while powering up --- up to 4 minutes with the USB SSD enclosure and a few seconds with the thunderbolt enclosure. Apple, it's time for a fix! I had to spend 106 Euros for a simple enclosure for my System SSD which worked just fine before Mojave!

I had this problem also since 10 nov 2018 when I bought a Samsung T5 500GB SSD and installed Mojave on it. Sometimes 4 minutes black screen before the AppleLogo appeared! Totally unacceptable, although workable... But I think i solved it. The problem appears to be that installing and updating the Samsung T5 Firmware needs at least one explicit eject and re-attach of this (external) SSD. But that is not possible while it is the disk where upon the OS is working! And re-assigning another disk to be the startup-disk does not count as a formal eject of the T5-ssd, because the restart takes place immediately without ejecting the ssd (so it seems). The solution:

1. Make (or use) a different, bootable startup disk, change startup-disk to that particular disk en Startup
2. Then update (safety first) the firmware on the still attached T5 ssd and EJECT and re-attach the T5 ssd (several times, if you want to be sure)
3. Assign Startup disk back to the T5 and Startup. This will take long, the first time, but there-after the slow-boot problem is gone!

Everything is probably caused by the fact that I had NOT activated the T5 SoftWare and FirmWare + ejected and re-attached the T5 BEFORE putting a new macOS on it. I did that deliberately, because I thought Mojave would know best how to format and install itself on this tiny little gem. That is true, but every time Mojave tried to re-start while installing etc. it got lost in space, because the T5-firmware was not effectively installed... And while working on the T5, we all could not eject it ... because it was the disk with the active OS on it...

So: an unsolvable loop. Which will come back every time when you update the firmware ! Because this firmware is not really designed for a bootable external ssd. And that is probably caused by the necessity to make attaching the data as secure as possible (that is what the T5-password-software tries to achieve).

Thus: first formatting and installing/updating the firmware on the T5 and immediately ejecting and re-attaching it is necessary. Mac Mojave will then re-format the ssd to APFS while installing, but the firmware is then already safely working in this little thing.

Same here. Went from seconds up to 3 minutes until Apple logo shows and another 2.5 minutes until login-screen. Everything was fine and very fast with High Sierra. I use an external SSD in a USB3 enclosure. But I have a longer boot time with the internal SSD in my Macbook Pro Retina 2015, too. I already did a PRAM and SMC reset, checked the drives with Disk Utility and so on.

What can be done?

Same here.

With AFPS external SSD High Sierra booting done, up to 20-30secs more or less.

Upgrated to Mojave, the booting is now extremely slow, up to 2-3 minutes more or less.

Anyone found solutions ?

Thanks in advance,

Best Regards.

Same here, there must be quite a few people who opted to run the OS from an external SSD rather than risking installing it internally as iMac's are just not very friendly for such upgrades.

I think in High Sierra it only gave you the option to stay as HFS+ if your OS SSD was internal? I dont recall having to force it to stay as HFS+ when I did that upgrade.

Considering APFS has been an option since High Sierra I would have hoped they were aware and found a solution for this by now. From what's been said here though it seems just be to with external (USB?) SSDs. This is similar to trying to run Windows on an external drive, as without a registry edit it cannot find the drive during the boot process.

It is also an annoyance for us Bootcamp users who can now only switch between Windows and OS X by holding ALT down during boot...another thing they haven't resolved yet :/

Sorry I haven't been able to offer any help though.

I recall to have my external USB3 SSD formatted with HFS+ and had the option to keep on HFS+ when installing HighSierra. This worked very well back then.

But still I can not understand, that the Trillion Dollar Company can not afford to test a new OS/filesystem booting of an external drive. I'm not sure, if they even want to fix this problem. Because after all, it's present since over one year when they introduced APFS with HighSierra. I am very disappointed.

Exactly the same problem on my external USB SSD. Very slow boot 1-2 min. since Mojave upgrade. On High Sierra with HFS+ the same drive started in ~20 sec. In Mojave from start to boot menu (holding Option key) takes ~30 sec. Then from boot menu to Mojave desktop 1-2 min.

My other problem is that my Recovery partitions disappeared after Mojave upgrade. My SSD is now formatted - first partition HFS+ (El Capitan), second partition is APFS with Mojave. No Recovery volumes appear in the boot menu. Booting to El Capitan (on the first HFS+ partition) is also slow (30 + 20) sec.

The Thunderbolt case allows TRIM command to pass to SSD, while USB case prevents the TRIM to reach the drive. There are a lot of users that complain about slow boot with APFS on High Sierra as well. Some claim that boot time is slow after enabling TRIM, others that after disabling TRIM. Another user restored his boot volume from Time Machine and his boot time reverted to normal.

I will try complete format and restore from backup, but I suspect that APFS requires TRIM to work.

Mojave requires APFS, but APFS does not require TRIM to work. Boot time got fast as soon as I put the SSD into the Thunderbolt 2 enclosure. I activated TRIM after that. As I understand it, TRIM is write-only and boot time is only affected by read-times. My SSD was pretty fast without TRIM. And it was still pretty fast with USB3 after log-in. The problem is the dark screen before Apple logo. I could live with the 40 seconds after that, but I cannot live with the 4 minutes plus before the Apple logo appears. The enclosure was pretty expansive: 106€ for a metal case with a pretty small board in it. I was lucky enough to at least have a thunderbolt 2 cable already.

Tommorrow I will try something. I will hook up my external SSD in a USB3 enclosure at my wifes Mac Mini. The Mini has not been updated to Mojave an runs on High Sierra. I want to have a look a what happens during the time before the Apple logo shows. The interesting part is, that my Macbook Pro shows long boot times even when I boot from the internal SSD with the USB3 SSD connected. And all my other drives start working, too (ie. the backup drives, although they lack a boot partition). Isn't that strange?

Just a thought but perhaps if your internal drive is formatted to HFS it does not work well with the external APFS drive when booting up the external drive. I noticed a similar issue when I formatted an external drive to APFS and installed High Sierra on and tested a few weeks ago when my internal was HFS with Sierra.

I wonder if Disk Utility shows "Solid State Drive: yes" for your SSD (in thunderbolt case). In Disk Utility select the drive, then Cmd+I to show Information window. My drive shows "Solid State Drive: no", but it's in a USB 3.0 case.

Also, do you see any Recovery partitions when you hold the Option key at startup?

Hello everyone,

i've found the solution.

A friend lent me a ssd thunderbolt drive, which I completely formatted.

With UtilityDisk have created a new APFS partition, and I used Carbon Copy Cloner to do a clone of the entire SSD USB3 to the new Thunderbolt SSD.

After the clone finished I've rebooted the mac, set the new drive as Startup Disk under the settings panel.

After the chime, now the apple logo appear after more or less 10 secs.

The boot time is now reduced from 2-3minutes to complessively about 20-30secs from the chime to OSX.

I've used only the Carbon Copy Cloner app, nothing else; nothing command settings, nothing particular settings.

So, in the conclusion, the problem is the USB3 enclosure.

Thank you for all, my friends !!

Sure,

he has a classic Lacie SSD Thunderbold 1TB (STFS1000401), but he is crazy 😀

He told me he paid him over € 500.

If the system goes and it is robust maybe I could think to buy the one with the lowest cost: D

No, no problems. Both formatted with APFS. All fine after I made the switch to the thunderbolt enclosure.
Since maverick1987 reports the same (he made that switch, too), I guess this is the only way to go for now.
But a pretty expansive one. For 106€ I could have bought another SSD......

It seems that this problem is not new. I tested rEFInd boot manager on my Mojave USB SSD and it's very slow, too. But I found that a user (see Uncle Sam post) in 2013 that fixed the slow boot problem by placing rEFInd boot partition on his internal HDD:

https://sourceforge.net/p/refind/discussion/general/thread/bc570433/#625f

I also noticed that boot is very fast if I force shut down (holding 5 sec.) the power button. Not a fix though.

I put my SSD in a Delock 42510 Thunderbolt case and the boot delay disappeared.

But this enclosure have two issues:

1. In idle mode SSD heats to 39-40 C (at 20 C ambient). It was ~30 C in the old USB enclosure.

2. The drive increases its S.M.A.R.T. property "192 Unsafe Shutdown Count" every time I issue a "Sleep" command. I have not such problem with my USB case (both cases are powered with external power adapters). I use DriveDx app to read S.M.A.R.T. data.

So, I can't recommend Delock 42510 case. Does anyone have any experience with AKiTiO eSata to Thunderbolt adapter?