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:
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:
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!
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
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 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!