Resolved 2017 iMac 27" external SSD as boot drive?

[lhammer610]

I just installed the Samsung T5 and used CCC to copy my startup drive over. I am surprised that the SSD does not show up as an option in the startup disk selection, but the Option key on startup works just fine.
I am running Mojave. I reformatted the SSD to HSF+. APFS was not an option. My internal startup drive is APFS
CCC says it might reformat the SSD to APFS, but it did not.
So the SSD stayed as HSF+

Is there any advantage or disadvantaged to leaving the Samsung T5 as HSF+.
Using Mojave, how would I convert the external SSD to APFS, if I wanted to?

I have a program called 'File Synchronization'. Can I use that to keep the old internal drive up to date, vs. buying CCC?

BTW, loading programs is blazing fast now. Thanks everyone for this thread.

 

[lhammer610]

My external SSD is formatted in Mac OS Extended (Journaled). It does not show up in the Preferences/Startup Disk option. I can boot into it if I hold down the Option key.

Is there a way to have the default boot drive the external SSD? Does it have to be formatted in APFS? If so, can I convert the external SSD from HFS+ to APFS without reformatting it?

 

[casperes1996]

My external SSD is formatted in Mac OS Extended (Journaled). It does not show up in the Preferences/Startup Disk option. I can boot into it if I hold down the Option key.

Is there a way to have the default boot drive the external SSD? Does it have to be formatted in APFS? If so, can I convert the external SSD from HFS+ to APFS without reformatting it?

Does it not even show when you are booted into it?

 

[lhammer610]

Does it not even show when you are booted into it?

No, it does not show up even when using the external SSD as the startup drive.

I found that I had to CCC clone back to my internal disk. I then went to Disk Utility. Under View, I selected Show All Devices. I selected the lowest level and reformat. I had to select GUID as the boot table. This enabled me to format as APFS. I then used CCC to copy my internal drive back to the SSD.

Since it is now formatted as APFS, it shows up under Preferences / Startup Disk. Works like a charm now. I no longer have to hold down Option on startup.

So the key is that the external SSD has to be reformatted as a GUID Partition Table (GPT) and APFS.

 

[Lankyman]

Although this thread is now quite old I thought I would add a comment. Why does everyone dash to get CCC or superduper to clone their drives when disk utility does the job just as well? Once you have your drive formatted boot the mac into recovery mode, select disk utility, select the newly formatted external drive then the restore button. You will then see a window with a dropdown, select MAC HD (not base system) click restore and it's job done. It will take a while depending on the amount of data. It works like a charm.

 

[steppinwolf]

Although this thread is now quite old I thought I would add a comment. Why does everyone dash to get CCC or superduper to clone their drives when disk utility does the job just as well? Once you have your drive formatted boot the mac into recovery mode, select disk utility, select the newly formatted external drive then the restore button. You will then see a window with a dropdown, select MAC HD (not base system) click restore and it's job done. It will take a while depending on the amount of data. It works like a charm.

Yes, an even older thread now, but I'm glad they've kept it open because it's still a useful and current topic. A friend of mine has an extremely sluggish 2017 iMac 21.5 that could benefit greatly from a fast external SSD. I'm thinking about recommending a T5 or T7 (non-touch).

I'm wondering if even now in 2023 it's still best to use HFS+ instead of APFS to avoid slow boot times. Her internal hard drive is APFS and currently running Monterey.

Disk utility format, boot to recovery and restore does sound like a quicker, simpler approach. But does it just restore a macOS image or actually clone apps and data from the internal to the external drive? If the former, then I could see why people who don't have current Time Machine backups might prefer cloning.

 

[lhammer610]

Yes, an even older thread now, but I'm glad they've kept it open because it's still a useful and current topic. A friend of mine has an extremely sluggish 2017 iMac 21.5 that could benefit greatly from a fast external SSD. I'm thinking about recommending a T5 or T7 (non-touch).

I'm wondering if even now in 2023 it's still best to use HFS+ instead of APFS to avoid slow boot times. Her internal hard drive is APFS and currently running Monterey.

Disk utility format, boot to recovery and restore does sound like a quicker, simpler approach. But does it just restore a macOS image or actually clone apps and data from the internal to the external drive? If the former, then I could see why people who don't have current Time Machine backups might prefer cloning.

I used APFS on the external SSD. I use that on the Time Machine externals also.

I used CCC to copy the drive because Disk Utility does not create a bootable copy back in Big Sur or perhaps previous to that. However, with the newest Mac OS, I am not sure that CCC can create a bootable copy. CCC has a disclaimer when trying to make a bootable copy stating that Apple has made it more difficult.

If your current hard drive is still working, I think the best solution is to format the external drive in APFS, then install the MacOS on it. Boot on the new drive and allow Migration Assistant to move everything over. That works very well for me.

However.... I did a clean install on Monterey. A number of people said that using Migration Assistant brings over all the old OS baggage and creates problems. I do not know if that is true.

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