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Slow boot (black screen before Apple logo) after HFS+ to APFS conversion of external boot SSD USB-C

lamBOO

macrumors newbie
Original poster
Sep 26, 2018
2
1
Hello! :)

I have an iMac 5K 2017 3.4 GHz and was running High Sierra with an external SSD disk (WD My Passport SSD 512GB) as boot disk. The macOS High Sierra allowed me to skip the conversion from HFS+ to APFS. The latter caused slow boot times last year. I was running fine with that system.

Yesterday, I upgraded to the new macOS Mojave and my external SSD was automaticially converted to APFS and the slow boot appeared again. There was no option to skip the conversion. Now, I have to wait around 60 seconds within a black screen before the Apple logo (or verbose log output holding CMD-V) appears. It seems, that the iMac is searching for volumes to boot from although I set the right start-volume in system's preferences.

I tried the following, all without success:
  • Complete reinstall of macOS Mojave to the WD My Passport SSD 512GB
  • Complete reinstall of macOS Mojave to another Samsung 840 EVO plugged into an UASP case
  • Complete reinstall of macOS Mojave to a USB3-stick
  • Deleting the internal Fusion Drive so that no other volumes are even visible to the iMac
  • Resetting NVRAM per terminal and reset-validation through "sudo nvram -xp"
  • Removing all peripherals except for the boot disk
  • Tried all four USB and all two USB-C/Thunderbolt connectors
All these solutions still have a ~60 seconds blackscreen in boot procedure before the Apple logo.

If the Apple logo appears after a while, the remaining boot is fast and takes about 20-30 seconds (like before with HFS+). Both disks don't support TRIM (seen in system report), therefore this should not be the issue.

I tried the safe mode but the boot time remains at overall 1 minute, 30 seconds. The safe mode applies right before the Apple logo, so my problem is before.

The final thing I did, was deleting all my OEM internal Fusion Drive and installed macOS Mojave with the APFS conversion there. And the boot time improved. I got overall 50 seconds (around 30 secs. in black screen) with another bootable external disk plugged in and 22 seconds with no peripherals plugged in.
Therefore I think, the problem has something to do with the initial scanning for bootable devices before the start volume is chosen and the Apple logo appears.

Today, I ordered two other external disk:

  • SanDisk Extreme Portable SSD 500GB
  • Samsung MZ-76E500B/EU 860 EVO
I will test if these will work.

I don't know how to solve my problem and use and external SSD with macOS Mojave and retain the fast booting time as it was the case with HFS+.


I hope someone can help me.
Thank you very much! :)
 

antisect

macrumors newbie
Sep 27, 2018
6
1
Ive got exactly the same issue, external sdd (crucial), black screen before boot (not timed it but its longer than a minute).
Was all fine before APFS.
Ive been considering installing the ssd internally but im not certain it would fix it

*EDIT
this is on iMac 21inch retina 2017
 
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heechee

macrumors newbie
Sep 28, 2018
5
1
Spain
I've got the same problem with Imac late 2013 with an external SSD disk usb 3.

No problem in High Sierra with HFS+. Mojave converted the SSD to APFS and the boot lasts several minutes (before the apple logo appears). Once the logo is on the screen, the boot time is the usual.

The only solution is come back to HFS+? Thanks
 
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heechee

macrumors newbie
Sep 28, 2018
5
1
Spain
I've more information about the problem:

- It seems that Mojave is checking the boot disk while the screen is black (the time before the logo appears). The led is continuously blinking on the boot disk.
- If I do a Disk First Aid (with command+R and Disk First Aid option), the time to check disk is long (more than 10-15 minutes). It checks every snapshot (luckily it only has 12 snapshots). It seems normal that time of check of an APFS disk is greater than of an HFS+ disk (on my macbook pro with internal ssd happens)
- In the first reboot after the check, the startup time is the same as when booting in High Sierra. Yes!!!
- But in the next reboots, the startup time is again very long.... No!!!
 
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lamBOO

macrumors newbie
Original poster
Sep 26, 2018
2
1
I've more information about the problem:

- It seems that Mojave is checking the boot disk while the screen is black (the time before the logo appears). The led is continuously blinking on the boot disk.
- If I do a Disk First Aid (with command+R and Disk First Aid option), the time to check disk is long (more than 10-15 minutes). It checks every snapshot (luckily it only has 12 snapshots). It seems normal that time of check of an APFS disk is greater than of an HFS+ disk (on my macbook pro with internal ssd happens)
- In the first reboot after the check, the startup time is the same as when booting in High Sierra. Yes!!!
- But in the next reboots, the startup time is again very long.... No!!!

With my setup, I can not confirm this behavior. After running First Aid on the Disk, the APFS container and the volume while booted with an macOS Mojave Installer USB-stick, the boot time was still slow because of a long black screen before the Apple logo.
[doublepost=1538399170][/doublepost]
The solution is to "go back to" booting and running Mojave under HFS+.

I've described the process here:
https://forums.macrumors.com/thread...ll-mojave-and-keep-hfs.2138162/#post-26479916

Thank you for the tip, this could be an option to have a fast boot again.

But 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.
 
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heechee

macrumors newbie
Sep 28, 2018
5
1
Spain
Thank you for the tip, this could be an option to have a fast boot again.

But 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 Agree with you!!
 
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kagharaht

macrumors 6502a
Oct 7, 2007
905
391
Same here iMac 14,1 bought new 2015. External SSD. Also lousy Fonts with Mojave. I'm just gonna give it a few months to see if Apple update resolves these things. If not, I'll downgrade to HS and be done with Apple updates and new stuff for awhile.
 
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heechee

macrumors newbie
Sep 28, 2018
5
1
Spain
Has anyone found an alternative or solution to this problem??

Should I buy a thunderbolt enclosure?
 
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Kargo

macrumors newbie
Sep 21, 2013
19
8
I had to follow Fishrrman’s advice above to fix the issue. I was having a problem with my external SSD where on APFS it was reaching a certain part during boot and not progressing, it would stay stuck on the Apple logo with a mid progress bar and not go any further - the only way to fix it would be to hold my finger on power for 5 seconds and try a second time, which oddly would work - though boot up was still 3 minutes or so.

Using CCC to clone my internal HDD onto the formatted external SSD under HFS+ has solved the issue. It boots in about 25 seconds without getting stuck once.

Just a bit gutting that the software won’t update seamlessly like before. As someone who was hoping to use the external SSD as a long term startup drive due to some bad sectors on the HDD, I would rather not have to boot to the HDD in order to do updates. Is it just the OS that will not offer updates or is it the same for iTunes, Pages, Safari etc.. ?
 
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XGO7

macrumors newbie
Aug 7, 2018
26
11
- In the first reboot after the check, the startup time is the same as when booting in High Sierra. Yes!!!
- But in the next reboots, the startup time is again very long.... No!!!

I had this same experience, went through trying all of the fixes. The only time it booted up fast was after targeting the SSD in safe mode for a restart.

I wonder, couldn't we just back up to another hard drive, format the external SSD, install Mojave under AFPS and then install files from the back up HD? Would that not be the easy way to solve the issue? Or are we screwed until apple finds a solution to this issue?

I honestly don't mind embracing AFPS if I can navigate past this issue.
 
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G4DPII

macrumors 6502
Jun 8, 2015
338
456
Had the same issue, converted to Absolute Pile oF S***, boot times went from 30 seconds to over 3 minutes - system became slow and laggy overall as well.. If you are using an external SSD the only solution is to go back to HFS+.

I gave up with Mojave and went back to High Sierra.

For now APFS is typical of today's Apple. Promises so much yet fails to deliver on almost every front.
 
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XGO7

macrumors newbie
Aug 7, 2018
26
11
Anyone with a better solution than the Fishrrman process? I do not have a second hard drive.

Hey, I gave up and installed the SSD running Mojave internally. It fixed everything. Computer was actually even faster than it was before.

I found an iMac SSD installation tutorial on YouTube. Its easier than it looks.
 
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Del Rei

macrumors member
Dec 13, 2017
47
4
Brazil
Hey, I gave up and installed the SSD running Mojave internally. It fixed everything. Computer was actually even faster than it was before.
I found an iMac SSD installation tutorial on YouTube. Its easier than it looks.

Hey, man!
Thanks for the advice. I'll look for that!
 
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Uwe Gross

macrumors newbie
Dec 23, 2018
1
0

I have tried the APFS to HFS converter and it worked great. The boot process went to normal so just takes about 15 - 20 secs.

BUT i now have the problem that i dont get 10.14.1 and 2 installed. The software update mechanism does not offer the update. When i downloaded the dmg and started the update the Process stops with an error that the boot media has the wrong file format.
 
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kagharaht

macrumors 6502a
Oct 7, 2007
905
391
I have tried the APFS to HFS converter and it worked great. The boot process went to normal so just takes about 15 - 20 secs.

BUT i now have the problem that i dont get 10.14.1 and 2 installed. The software update mechanism does not offer the update. When i downloaded the dmg and started the update the Process stops with an error that the boot media has the wrong file format.
Thats why I didn't do it. I'll just have to live with it or wait for Apple to FIX. Which I've read that the recent beta is suppose to fix this problem.
 
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mode11

macrumors 6502
Jul 14, 2015
367
152
London
A few months later, has anyone found a fix for this? I'm booting off a Samsung 500GB T5 SSD on my Late 2013 27" iMac at work, and get the long boot delay with black screen. I formatted the USB SSD as APFS, then cloned the existing High Sierra install from the internal HDD to the SSD. All working great except for the boot up time (annoying, as slow reboots, including reopening apps, were one of the reasons for the upgrade).

If I install Mojave, will this likely solve the problem? I had something similar with my Mac Pro at home, and found that backing up to Time Machine then restoring, permanently solved the problem.
 
Comment

Del Rei

macrumors member
Dec 13, 2017
47
4
Brazil
A few months later, has anyone found a fix for this? I'm booting off a Samsung 500GB T5 SSD on my Late 2013 27" iMac at work, and get the long boot delay with black screen. I formatted the USB SSD as APFS, then cloned the existing High Sierra install from the internal HDD to the SSD. All working great except for the boot up time (annoying, as slow reboots, including reopening apps, were one of the reasons for the upgrade).

If I install Mojave, will this likely solve the problem? I had something similar with my Mac Pro at home, and found that backing up to Time Machine then restoring, permanently solved the problem.

Didn't solve here.
Still 20~25 sec before shows apple logo.
 
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mode11

macrumors 6502
Jul 14, 2015
367
152
London
Updating to Mojave didn't solve the issue on my Mac Pro either, though the issue there was a little different. I was booting High Sierra from a SATA SSD connected to an internal port. I didn't get a black screen, but the progress bar would pause for a minute or so during startup, before progressing quickly for the last part. This was quite a common issue, and I believe was related to TRIM on APFS drives (disabling TRIM made the drive boot up as it should, i.e. fast). I tried upgrading to Mojave but there was no change.

The solution someone discovered was to back up to Time Machine then do a full restore. I was sceptical but it worked perfectly and has been fine since. As USB drives don't support TRIM, however, I don't know if the same factors are at work here; it could be something completely different.
 
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BH1947

macrumors newbie
Sep 24, 2016
11
6
UK
Hello! :)

I have an iMac 5K 2017 3.4 GHz and was running High Sierra with an external SSD disk (WD My Passport SSD 512GB) as boot disk. The macOS High Sierra allowed me to skip the conversion from HFS+ to APFS. The latter caused slow boot times last year. I was running fine with that system.

Yesterday, I upgraded to the new macOS Mojave and my external SSD was automaticially converted to APFS and the slow boot appeared again. There was no option to skip the conversion. Now, I have to wait around 60 seconds within a black screen before the Apple logo (or verbose log output holding CMD-V) appears. It seems, that the iMac is searching for volumes to boot from although I set the right start-volume in system's preferences.

I tried the following, all without success:
  • Complete reinstall of macOS Mojave to the WD My Passport SSD 512GB
  • Complete reinstall of macOS Mojave to another Samsung 840 EVO plugged into an UASP case
  • Complete reinstall of macOS Mojave to a USB3-stick
  • Deleting the internal Fusion Drive so that no other volumes are even visible to the iMac
  • Resetting NVRAM per terminal and reset-validation through "sudo nvram -xp"
  • Removing all peripherals except for the boot disk
  • Tried all four USB and all two USB-C/Thunderbolt connectors
All these solutions still have a ~60 seconds blackscreen in boot procedure before the Apple logo.

If the Apple logo appears after a while, the remaining boot is fast and takes about 20-30 seconds (like before with HFS+). Both disks don't support TRIM (seen in system report), therefore this should not be the issue.

I tried the safe mode but the boot time remains at overall 1 minute, 30 seconds. The safe mode applies right before the Apple logo, so my problem is before.

The final thing I did, was deleting all my OEM internal Fusion Drive and installed macOS Mojave with the APFS conversion there. And the boot time improved. I got overall 50 seconds (around 30 secs. in black screen) with another bootable external disk plugged in and 22 seconds with no peripherals plugged in.
Therefore I think, the problem has something to do with the initial scanning for bootable devices before the start volume is chosen and the Apple logo appears.

Today, I ordered two other external disk:

  • SanDisk Extreme Portable SSD 500GB
  • Samsung MZ-76E500B/EU 860 EVO
I will test if these will work.

I don't know how to solve my problem and use and external SSD with macOS Mojave and retain the fast booting time as it was the case with HFS+.


I hope someone can help me.
Thank you very much! :)
[doublepost=1553166837][/doublepost]Hi, I too had this issue but after many hours of searching online I found a solution that worked for me. Open System Preferences - Select Startup Disk - Click on your startup disk even if you see it already selected - Restart your computer and hopefully all will be fine again.
 
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Marx55

macrumors 68000
Jan 1, 2005
1,773
599
Have the issues of Mac with Samsung Portable SSD T5 formatted as APFS been fixed with macOS 10.15 Catalina?

- Slow booting Macs.
- No booting Macs with T2 chips.
 
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