Slow boot time after update to Mojave - External SSD

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maverick1987 Author

Level 1

34 points

Slow boot time after update to Mojave - External SSD

Hello!

I have a iMac 21" 4k 3,1ghz 2015. I installed an external SSD Samsung 860 Evo 512gb to avoid losing the Apple 1yr warranty if I opened my iMac by myself.

So when I was using APFS format and OSX High Sierra, my iMac used to start, then 2 seconds with a completely empty screen(black) looking for the boot SSD, then the Apple logo appear and it would take another 18 seconds for the system to start completely.

Total boot time = ~20secs.

Now I installed the new MacOS Mojave and my current boot time are very very slow; when I turn on the computer the screen stills black for 2 minutes more or less "looking for my external boot SSD" and then the Apple logo appear and +18secs the system starts.

My current boot time = More than 2~3minutes!!!!

I have also a MacBook Pro 2017 TouchBar and TouchID with 512GB integrated SSD also with APFS format, and update this from High Sierra to Mojave at the same day/time to the iMac. Fortunately the MacBook Pro booting done in about 20secs.

So... There is any solution for fixing this "everlasting" blank screen when booting the iMac with MacOS Mojave and external SSD with APFS format?

I've researched about this, but I can't find anything to solve it. So, I hope someone here may help me!

Thanks!

iMac, macOS Mojave (10.14)

Posted on Sep 28, 2018 8:34 AM

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Answer 1

Best reply

maverick1987 Author

Level 1

34 points

Oct 3, 2018 11:44 PM in response to maverick1987

Hello everyone,

i've found the solution.

The reset of the SMC not work, during the night (all the night) I shutdown the mac and disconnect the power, so the power cord is disconnected for about 7-8 hours.

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 (can be the TRIM functionality that is not present to the USB3 enclosure, even if it supported the TRIM and the UASP functionality.

Thank you for all, my friends !!

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Answer 2

Oct 17, 2018 5:24 AM in response to maverick1987

Well guys, MacBook Pro 15 2013, i7, 16gb, Dual video, 51 2gb SSD. After update my Mac to Mojave, boot take something like one minute or more to boot up. Try SMC Reset, Pram, nothing change. So I start to look the date of my files. And I found this guys (image). After moving this guys to trash, Mac speed up again! 23 seconds and voila! Everything ok. Hope this help! And sorry for my bad English, Brazilian here.

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Answer 3

sterling r

Community Specialist

Sep 29, 2018 11:55 AM in response to maverick1987

Hello maverick1987,

Thank you for using Apple Support Communities!

I understand from your post that after updating to macOS Mojave it takes your iMac longer to boot up from your external SSD than previously. Resetting the System Management Controller may help in a situation like this. The following article will provide you with the steps on how to reset the System Management Controller:

How to reset the System Management Controller (SMC) on your Mac - Apple Support

Best Regards.

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Answer 4

barcapat

Level 1

7 points

Oct 4, 2018 4:22 AM in response to maverick1987

I have the same slow boot problem on my iMac, since upgrade to Mojave.

Exact times are:

restart machine and screen black for 1 minute 16 seconds
Apple logo displays then password input appears, enter password
booting continues and can eventually use the Desktop after 2 mins 16 seconds

I tried resetting the SMC but that made no difference.

What's marked as 'solved' for this is a big workaround using another external drive - hardly a solution for most people.

This thread should be re-opened and hopefully Apple will sort it out in the next update.

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Answer 5

Oct 5, 2018 4:10 AM in response to maverick1987

Same thing in here, after the update 2-3 minutes to boot.

Black screen 1st for quite a while and then Mac Logo.

I have tried:

unplugging all the cables and plug in again.
re-select the startup disk and selecting the external SSD disk again
Shutdown the iMac and then press and hold the power button until turns on

So far no improvement

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Answer 6

Jan 22, 2019 6:25 PM in response to PF2UK

Having read positive reviews on 10.14.3 solving this issue, I went ahead to download its COMBO update, and to my horror, it refused to install and update my external USB 3 Drive. The SSD drive is simply not selectable.

So I decided to try to update to 10.14.3 directly via Software Update instead, and it works!!

My iMac finally boots up swiftly like it used to.

I subsequently apply the 10.14.3 COMBO Update through the system, and this time it went through without any problem.

I'm glad the issue is resolved, for me at least.

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Answer 7

Sep 30, 2018 4:16 AM in response to maverick1987

If you put that Samsung SSD into a USB2 drive enclosure, you can expect that speed limitation on first boot, and waking from sleep. If it is in a USB3 enclosure, swap out that USB3 drive cable for another one, and retest boot time.

If you have any USB2 connections to your iMac, or any hub, unplug them before booting and see if these peripherals are impacting your boot time.

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Answer 8

maverick1987 Author

Level 1

34 points

Sep 30, 2018 7:41 AM in response to VikingOSX

Hello VikingOSX,

I use a USB3 driver enclosure and have changed the drive cable with another 2 other external disk, but nothing.

I've a USB3 external hub, I've disconnected this before I start the iMac but nothing.

I have the same problem in both cases.

Other solutions ?

Thank you very much,

Best Regards

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Answer 9

maverick1987 Author

Level 1

34 points

Sep 30, 2018 7:52 AM in response to maverick1987

I've seen the Paragon software converter from APFS to HFS+ but I don't know if can resolve my problem (i don't know if my problem can be the APFS format of the external SSD Drive). Also I don't know if Mojave can start with the HFS+ format (I don't see anymore the convert voice under the Utility Disk app with Mojave).

Anyone that has used the Paragon software to convert from APFS to HFS+ the main partition with Mojave already installed ?

Thank you very much

Best Regards

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Answer 10

arivag

Level 1

4 points

Sep 30, 2018 12:26 PM in response to maverick1987

Hi

I have same problem. I update to Mojave and my iMac boot in 4 mim (20 seconds in High Sierra).

Using TimeMachine to back High Sierra, iMac boot in 20 seconds. Then, I make a clean install of Mojave and I have same problem again. iMac 2015 boot in +-4 min.

My external ssd is Samsung 850 Evo.

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Answer 11

maverick1987 Author

Level 1

34 points

Sep 30, 2018 1:03 PM in response to arivag

Hi Arivag,

after upgrade to Mojave I don't update my TimeMachine backup; so the backup is yet to High Sierra.

I've read that I don't recovery the TimeMachine backup if the current OSX is higher than the backup.

How did you restore the backup to bring the system back to the previous version?

Can you reinstall Mojave using the HFS+ format for your external SSD ?

Thank you very much,

Best Regards

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Answer 12

polo91

Level 1

13 points

Sep 30, 2018 11:58 PM in response to maverick1987

I have the same problem.

(iMac late 2012, 27”) even with 24gb ram my external ssd samsung evo 850 starts in 3,5 minutes after updating to mojave.

I didnt know high sierra runs with apfs (boot time was 25 secs) and that didnt cause any problems, so i think the problem is in mojave not apfs. (I didnt replace the cable for another) i tried to clean install mojave but that didnt help. Same speed

I tried to enabled trim. And disabled trim. Same speed

I tried another ssd - samsund t5. Same speed

I tried to make a time machine backup of mojave to internal hdd, and restore to ssd again. Same speed.

(Last thing - i want to try different cable or enclosure)

Can we hope the next Mojave update will solve this problem?

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Answer 13

Oct 1, 2018 4:11 AM in response to maverick1987

I have the same kind of issue, not with an external but internal SSD in my Mac Mini.

Observing the boot in verbose mode shows the hold-up occurs when the messages include 'com.apple.signature3 (flsymmetric-Pause=1)' and 'com.apple.xpc.launchctrl is not declared debuggermacOSTaskPolicy' and 'Debugger pci pause: SDXC'

Maybe that will help somehow..

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Answer 14

maverick1987 Author

Level 1

34 points

Oct 1, 2018 5:24 AM in response to markfromroermond

Hi folks,

I've tried to boot in verbose mode, but for me the slow boot is when searching for the "starting point" (EFI Partition, or similar, when trying to search the system boot). After I see the apple logo MacOS boot in about 10-15 secs, the problem is before the logo, between the chime and the logo (I think, the chime is for the starting of the mac -- check hardware failure, check hardware peripherals and so on -- and the logo appears only when the boot partition and information are found, similar to the POST status on old BIOS).

If the system not found the correct partition scheme, boot system, boot disk and so on, slows down the boot to search for this information.

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Answer 15

arivag

Level 1

4 points

Oct 1, 2018 5:59 AM in response to maverick1987

Hi.

You can restore any point saved in TimeMachine.

I install Mojave on september24 and i kept making backups in TimeMachine.

Yesterday I restored the iMac with a backup of September 23 and returned to Hight Sierra whithout problems.

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