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Is anyone successfully booting Mojave on an external APFS-formatted SSD?

smirk

smirk

macrumors 6502a
Original poster
Jul 18, 2002
694
56
Orange County, CA
Hi, I recently got a Samsung T5 external SSD to use as a new boot drive for a late-2012 iMac. Formatted as APFS, used CCC to clone the internal drive to the SSD. Once booted, it is very fast.

However, there is a 1-2 minute-long delay in between the startup chime and the system actually booting, that only occurs if the T5 is connected -- regardless of what drive is selected as the boot drive.

I spoke with Samsung and they are aware of the issue. Carbon Copy Cloner also has a comment about it on their site. Samsung claims the issue exists with many SSDs, not just theirs. A CCC Support person said they've only heard about the T5 having this issue.

I'm trying to decide how to resolve my issue. One work around is to format the drive as HFS+, but I'd rather not create an unsupported environment. So maybe an easier solution is to just buy a different drive.

Can anyone confirm that their non-T5 SSD formatted as APFS either boots quickly without the startup lag, or that their non-T5 SSD does have the startup lag?

Thanks!

-----

Edit: I guess my question is this - Is anyone booting Mojave on an APFS-formatted SSD that is connected via USB, without a lengthy boot delay? If so, what SSD are you using?
 
Last edited:
How do you have the external drive connected?

I have booted from many SSDs, even ones in a RAID0 and never had a long time to wait before the boot chime from a cold start up.

But, I noticed something similar the other day on my Late 2012 iMac. I found a good deal for a thunderbolt LaCie rugged drive on eBay a week ago, I purchased a Samsung 860Evo to put inside it.

The drive ran fine with the HDD it came with on both Thunderbolt and USB3. After swaping the drive for the SSD I bought, it ran a lot faster with Thunderbolt, stopped working with USB3, and had a crazy long boot time if booted up using the internal Fusion Drive but just had the LaCie drive plugged into the USB3.

Probably a totally different issue.
[doublepost=1544652326][/doublepost]
vertical smile said:
and had a crazy long boot time if booted up using the internal Fusion Drive but just had the LaCie drive plugged into the USB3.
Click to expand...

And this is after the SSD was installed in the LaCie Drive, not before.
 
Unless you buy an expensive Thunderbolt External Drive or format it in unsupported HFS, it's all USB SSD external drive. There is a thread on Apple communities. I can't remember the link and Apple search feature on their communities is a joke of a search engine.
 
@vertical smile: The T5 is connected via one of the USB 3 ports on the back of the iMac.

To clarify, the long delay is after the boot chime and before it actually starts booting up.

The issue you posted about with the crazy long boot time could actually be the same issue. It seems occur whenever the T5 (and possibly other brands?) is formatted with APFS and is connected via USB -- even if the system is booting to the internal drive.
[doublepost=1544653034][/doublepost]
kagharaht said:
Unless you buy an expensive Thunderbolt External Drive or format it in unsupported HFS, it's all USB SSD external drive. There is a thread on Apple communities. I can't remember the link and Apple search feature on their communities is a joke of a search engine.
Click to expand...

Thanks for the reply. Are you sure it's "all" USB SSD external drives, and maybe not just some that use a particular USB controller or something? Because lots of people seem to use USB SSD drives without this issue, and the Support guy at Carbon Copy Cloner said they've only heard about the T5 exhibiting this issue.
 
smirk said:
It seems occur whenever the T5 (and possibly other brands?) is formatted with APFS and is connected via USB -- even if the system is booting to the internal drive.
Click to expand...

This might be correct, as I first tried HFS but later switch to APFS.

A side note, I had much faster write speeds with APFS than HFS, but similar read speeds.

Maybe I might switch it back to HFS and leave it plugged in during a start up and see if the issue is still there.
 
smirk said:
@vertical smile: The T5 is connected via one of the USB 3 ports on the back of the iMac.

To clarify, the long delay is after the boot chime and before it actually starts booting up.

The issue you posted about with the crazy long boot time could actually be the same issue. It seems occur whenever the T5 (and possibly other brands?) is formatted with APFS and is connected via USB -- even if the system is booting to the internal drive.
[doublepost=1544653034][/doublepost]

Thanks for the reply. Are you sure it's "all" USB SSD external drives, and maybe not just some that use a particular USB controller or something? Because lots of people seem to use USB SSD drives without this issue, and the Support guy at Carbon Copy Cloner said they've only heard about the T5 exhibiting this issue.
Click to expand...
I have a Sandisk 1TB SSD on an external USB3 drive. I have the 2 min or more startup delay.
OYEN MiniPor 3.1 ASMedia Technology Inc. for external enclosure.
 
Suggestion:

Erase the external SSD to Mac OS extended with journaling enabled (HFS+).

Then, use CCC to "re-clone" the internal drive to the SSD.

NOW try shutting down and rebooting to the external as the boot drive.

Any difference?

I have Mojave installed and running on an external SSD under HFS+, and it boots up "just like that" -- very quickly.
 
Fishrrman said:
Suggestion:

Erase the external SSD to Mac OS extended with journaling enabled (HFS+).

Then, use CCC to "re-clone" the internal drive to the SSD.

NOW try shutting down and rebooting to the external as the boot drive.

Any difference?

I have Mojave installed and running on an external SSD under HFS+, and it boots up "just like that" -- very quickly.
Click to expand...

Thank you, I've read your posts about this and they are both interesting and helpful. I don't doubt that formatting the drive as HFS+ will stop the bootup delay. But doing so will introduce complications that while I could handle, the owner of the iMac I'm working on probably couldn't.
 
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I have the very same problems. I have an APFS SSD in Sonnet Echo 15+.
Is HFS+ the only to do this?
 
I have an unusual situation. Mac Mini 2014 has Mojave on external SSD through USB. Boots fine when there is nothing else connected via USB. But when I have the WD MyBook, which is my Time Machine, connected, the boot goes directly to the slow internal HDD. Does not matter what is selected via startup disk.

Also, none of the keyboard shortcuts work on boot (option, for instance) when booting to internal HDD.
 
Ndbowden said:
I have an unusual situation. Mac Mini 2014 has Mojave on external SSD through USB. Boots fine when there is nothing else connected via USB. But when I have the WD MyBook, which is my Time Machine, connected, the boot goes directly to the slow internal HDD. Does not matter what is selected via startup disk.

Also, none of the keyboard shortcuts work on boot (option, for instance) when booting to internal HDD.
Click to expand...

Do you by any chance have any USB devices going through a USB hub?
 
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