2018 MacBook Pro w/T2 chip: can't boot from clone

[stradify]

In Recovery mode I reset security preferences to none and allowed boot from external drive yet my 2018 MacBook Pro w/touchbar defaults to the internal hard drive instead of the CC clone on my Samsung evo 850 external drive which does show up in the system preferences as a bootable drive. It also shows up on the desktop.
Any ideas on how to get the laptop to boot from the external SSD or why it won't?
The first time I tried this was with a clone of my iMac 2015 which also is running Mojave. I wrote Bombich and they thought that might be the reason it wouldn't boot properly so I made a clone of the MacBook Pro to test that theory and I'm still having the same problem.
NB: System Preferences>Startup Disk shows the Carbon Copy SSD clone as a bootable drive.
Any ideas on what I'm missing here?

 

[CoastalOR]

Can you boot to the clone using the boot manager (holding the Option key at startup)?

 

[chabig]

System Preferences>Startup Disk shows the Carbon Copy SSD clone as a bootable drive.

Did you actually select it as the boot drive in System Preferences > Startup Disk? And did you click to allow external booting?

 

[stradify]

Can you boot to the clone using the boot manager (holding the Option key at startup)?

Holding the Option key while booting allows me to choose the clone but it still boots to the internal HD.

 

[Ploki]

Holding the Option key while booting allows me to choose the clone but it still boots to the internal HD.

really?
Try renaming the clone to something else.
I'm booting from external like a madman and it works consistently.

 

[chrfr]

Holding the Option key while booting allows me to choose the clone but it still boots to the internal HD.

Is your clone formatted as APFS? The T2 computers won’t boot from HFS+.

 

[stradify]

I tried renaming the clone to something else but that didn't help.
The clone is, and has been, formatted in APFS.
I've been working with Mike Bombich of CCC on this and it's looking like the Sabrent connector is the problem.
I've ordered an enclosure, that Mike recommended, with USB C connections.
When it gets here I'll give it a go and let you know what happens.
By the way, I reformatted the partition containing the clone, and did a clean install of Mojave and then tried to boot from it.
No luck. Fortunately, that partition was able to boot on my 2015 iMac. That's how it's now narrowed down to the connector.
Another clue, I also couldn't install Mojave onto the new APFS partition with the MB Pro. Tried Recovery Mode as well as a USB installer.
I had to use my iMac to do the clean install. After trying to do a clean install of Mojave using the MBPro this is what I got (see attached file).

This is the connector in question: https://www.amazon.com/Sabrent-2-5-...&sr=8-2-fkmr0&keywords=sabrent+connector+SATA

Hey Ploki,
What Security setting are you using that allows you to boot like a mofo?
I've tried Medium and No Security. My guess is if you're booting from an external drive with Mojave then Medium is fine?

 

[SoyCapitanSoyCapitan]

Yeah you have to boot into recovery mode and allow the computer to boot from external volumes. This is a new security procedure to prevent someone using an external disk on a stolen Mac to wipe the internal drive.

 

[eagerwu]

Yeah you have to boot into recovery mode and allow the computer to boot from external volumes. This is a new security procedure to prevent someone using an external disk on a stolen Mac to wipe the internal drive.

And by doing so a clean install of the system is required to switch security level in recovery mode.

 

[chabig]

Did you click to allow booting from external devices? (see post #3)

 

[Ploki]

What Security setting are you using that allows you to boot like a mofo?
I've tried Medium and No Security. My guess is if you're booting from an external drive with Mojave then Medium is fine?

i think medium... gotta recheck tho, i'm not really picky about boot security.

Booted fine to a clone and to a different system. (I have an external SSD with system for experimenting)

 

[stradify]

Did you click to allow booting from external devices? (see post #3)

Yes, as I stated in my 1st post: "In Recovery mode I reset security preferences to none and allowed boot from external drive..."

 

[stradify]

Resolved: The Samsung EVO 850 500 GB SSD is unable to function properly with my 2018 MacBook Pro w/TouchBar.
I tried a different SSD onto which I downloaded a fresh copy of Mojave using the laptop and it booted just fine.
Is it that only my Samsung copy is bad or is it more widespread?
Anyone employing Samsung SSD's as clones that are not having problems booting them from their new MacBook Pro's?
[doublepost=1541202117][/doublepost]So, I'm looking for a replacement SSD on Best Buy's website and lo and behold, the first review I find of a Samsung SSD:

Problems booting MacBook Pro 2018 and USB-C
Posted 3 weeks ago
Physical size is awesome, solid looking metal smooth case.
On a 2018 MacBook Pro it tests read/writes of about 500Mb/s each when using the supplied USB-C cable, and 320&350Mb/s using the USB-C to USB-A cable.
Problem with Mojave when used as a boot drive, system is incredibly slow (4-6 minutes to boot) with numerous odd errors when using all USB-C connections. When using the USB-C to USB-A cable all works great though slower as the drive's r/w is slower. Tried formatted as APFS and then reformatted as HFS+, same issue - totally unusable as a boot drive when using USB-C. Other SSD's I have don't have this issue. Would not recommend if you are looking to use this as a backup boot drive.

Looks like it isn't just my copy.

Here's the link to the review: https://www.bestbuy.com/site/samsun...tate-drive-deep-black/6026202.p?skuId=6026202

 

[chrfr]

Resolved: The Samsung EVO 850 500 GB SSD is unable to function properly with my 2018 MacBook Pro w/TouchBar.

I'm confused. Do you have a Samsung T5 or a Samsung 850 Evo drive?

 

[stradify]

I'm confused. Do you have a Samsung T5 or a Samsung 850 Evo drive?

I have the Samsung 850 EVO but I was looking at the T5 as a possible replacement. Now that isn't going to happen based on my experience and that review. I'll go with another brand. I have written to Samsung so perhaps they will have a firmware fix in the near future.

 

[chrfr]

I have the Samsung 850 EVO but I was looking at the T5 as a possible replacement. Now that isn't going to happen based on my experience and that review. I'll go with another brand. I have written to Samsung so perhaps they will have a firmware fix in the near future.

What sort of enclosure do you have the 850 in?

 

[stradify]

The enclosure is an OYEN Minipro USB-C portable drive USB 3.1 Gen 2

 

[Fishrrman]

chfr wrote:
"Is your clone formatted as APFS? The T2 computers won’t boot from HFS+."

Have you tried this yourself?
Is it "documented" someplace?

Just wondering...

----------------
stradify wrote:
"The enclosure is an OYEN Minipro USB-C portable drive USB 3.1 Gen 2"

I'm wondering if it could be the enclosure that is causing the problems (and not the drive inside it).

I have the previous Minipro USB3 version. Great enclosure, built like a tank, but wondering if it still could have a problem with its circuit board inside?

 

[stradify]

Yes, the cloned partitions were both APFS. Since I had no trouble booting with the SP SSD I'm thinking Samsung's SSD's could be having problems booting onto T2 chip enabled MacBook Pro's.

Here's a link to CCC's website that goes into how to trouble shoot T2 chip enabled Mac's to be bootable:
https://bombich.com/kb/ccc5/help-my-clone-wont-boot

 

[stratokaster]

I haven't used my 850 EVO as an external drive, however I used it as a boot drive in one of my previous MBPs and it was a complete disaster: the laptop randomly refused to boot from this drive, and even when it booted just fine, I would get random freezes. Exchanged it for a Crucial SSD and it was a very smooth experience afterwards.

 

[Fishrrman]

chrfr wrote in post 6 above:
"Is your clone formatted as APFS? The T2 computers won’t boot from HFS+."

I think this is the case only in SOME situations.
If the HFS+ clone has been encrypted, the t2 can't boot from it.
Please read on.

The following is from CCC's page "Help my clone won't boot":
https://bombich.com/kb/ccc5/help-my-clone-wont-boot
==========
T2-based Macs can't boot from encrypted HFS+ volumes
Our testing has confirmed that Macs with Apple's T2 controller chip cannot boot from an encrypted, "Mac OS Extended"-formatted, external volume. Booting from an external volume works fine in general, but if your external disk is formatted using Apple's legacy HFS+, "Mac OS Extended" format, enabling FileVault on that volume will render it non-bootable, producing an error message like this on startup:

A software update is required to use this startup disk. You can update now or select another startup disk.
==========

But -- Mr. Bombich says nothing about a completely UNENCRYPTED HFS+ cloned backup not being able to boot a Mac with a t2 inside.

I don't have a Mac with a t2 inside yet.
I DO have an external SSD that is formatted in Mac OS extended (NOT encrypted) with Mojave on it.

I believe this is bootable, but as I said, no Mac by which to test it... yet.

 

[chrfr]

chrfr wrote in post 6 above:
"Is your clone formatted as APFS? The T2 computers won’t boot from HFS+."

I think this is the case only in SOME situations.
If the HFS+ clone has been encrypted, the t2 can't boot from it.
Please read on.

The following is from CCC's page "Help my clone won't boot":
https://bombich.com/kb/ccc5/help-my-clone-wont-boot
==========
T2-based Macs can't boot from encrypted HFS+ volumes
Our testing has confirmed that Macs with Apple's T2 controller chip cannot boot from an encrypted, "Mac OS Extended"-formatted, external volume. Booting from an external volume works fine in general, but if your external disk is formatted using Apple's legacy HFS+, "Mac OS Extended" format, enabling FileVault on that volume will render it non-bootable, producing an error message like this on startup:

A software update is required to use this startup disk. You can update now or select another startup disk.
==========

But -- Mr. Bombich says nothing about a completely UNENCRYPTED HFS+ cloned backup not being able to boot a Mac with a t2 inside.

I don't have a Mac with a t2 inside yet.
I DO have an external SSD that is formatted in Mac OS extended (NOT encrypted) with Mojave on it.

I believe this is bootable, but as I said, no Mac by which to test it... yet.

Indeed, I was mistaken. I took a Samsung 850 Evo, updated it to 10.13.6 with the latest security update (formatted as HFS+) and booted my 2018 MBP from it. I left the security option at high and enabled the option to boot from an external device.
The 2018 MacBook Pro does not allow the installation of High Sierra onto an external drive that's not formatted as APFS; I had to use a different computer to get 10.13.6 on the disk. It may be that I was thinking of the internal drive as being what requires APFS, which would make sense.

 

[Fishrrman]

chrfr wrote:
"ndeed, I was mistaken. I took a Samsung 850 Evo, updated it to 10.13.6 with the latest security update (formatted as HFS+) and booted my 2018 MBP from it. I left the security option at high and enabled the option to boot from an external device."

That's good to know.

But what I'd really like to find out if a copy of Mojave, running on an unencrypted HFS+ external drive, can boot a t2-equipped Mac.

One other thing I'd like to try (but don't have the t2 Mac with which to do it:
1. Put a copy of Mojave on an unencrypted HFS+ drive.
2. Boot the t2 Mac up in Mojave/HFS+
3. Open Disk Utility and attempt to ERASE the internal drive to HFS+ (Mac OS extended with journaling enabled)
4. Would it work? Inquiring minds want to know.
(I'm guessing it probably won't, even with every possible security feature disabled, but want to give it a try anyway)

 

[stradify]

Indeed, I was mistaken. I took a Samsung 850 Evo, updated it to 10.13.6 with the latest security update (formatted as HFS+) and booted my 2018 MBP from it. I left the security option at high and enabled the option to boot from an external device.
The 2018 MacBook Pro does not allow the installation of High Sierra onto an external drive that's not formatted as APFS; I had to use a different computer to get 10.13.6 on the disk. It may be that I was thinking of the internal drive as being what requires APFS, which would make sense.

chrfr,
Is your MacBook Pro's SSD running Mojave? If so, try booting from a clone of it onto the Samsung EVO 850 with security set to allow boot from external and see if you can boot from the SSD. If I'm correct, that there's a problem with Samsung SSD's firmware, then it won't boot.