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Install To External SSD?

PBG4 Dude

PBG4 Dude

macrumors 601
Original poster
Jul 6, 2007
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I’ve tried to install Mojave to an external SSD multiple times but keep ending up with the circle with a slash through it icon instead of booting.

Has anyone installed to an external SSD successfully? I have an Apple (Toshiba) OEM 128GB SSD in an external closure and have never had issues installing an OS on it before Mojave. Even reinstalled High Sierra to external then booted that version of High Sierra to upgrade. Still no luck.

Installing to a Parallels image now to see if this will work for me. No way am I installing beta 1 to my internal SSD.

Oh yeah, this is on a 2017 15” MBP so it should be compatible.
 
Could it maybe be APFS issue? Not sure if Mojave is that only but possibly you need to format the external SSD as APFS rather than HFS + /MacOS Extended Journaled?

Just guessing as I'm not sure if you can even format external drives as that but worth a go if so!
 
I formatted as APFS after my initial try on HFS+ failed.

Edit: It’s even running on the external in a Parallels container now. Just can’t get it to install directly.
 
Today I installed Mojave on an external SSD sitting in an OWC USB3 housing and it worked fine. The drive was formatted to HFS+ but was reformatted as APFS during install. Thats with an iMac i7 Late 2012. How is your SSD connected to the Mac? Does the drive get enough power?
 
SSD is connected directly to MBP via USB-C cable. Was able to install Mojave to a parallels VM file on the external SSD without issues.

This is an SSD I’ve used for years to test beta OSs and still works on High Sierra. I even tried a different USB3 HDD to see if that would make a difference.

Tried different ports on the MBP and everything. Have no idea why it won’t work. I’ve even redownloaded the install image in case the first download was corrupted. Just can’t figure it out.
 
c-3po said:
Wow, sorry to hear that. I am running out of ideas I am afraid.
Click to expand...
Thanks for trying. :)

Just don’t know what to try next, other than wait for beta 2. While Mojave runs in Parallels, it can’t see the touchbar and other hardware.
 
c-3po said:
Today I installed Mojave on an external SSD sitting in an OWC USB3 housing and it worked fine. The drive was formatted to HFS+ but was reformatted as APFS during install. Thats with an iMac i7 Late 2012. How is your SSD connected to the Mac? Does the drive get enough power?
Click to expand...
So Mojave doesn't ask you if you want to re-format to APFS ?

If so, bad news for HFS+ which although old .. works and is reliable. APFS is new and problomatic at least in Hi Sierra.
 
So, the external SSD that won’t boot on my 2017 MBP is currently working as expected when using it with my 2012 MBA. Now I’m really confused. Didn’t reload it or anything. Just connected to my MBA and held down Option on boot to select it.

Going to retry the external drive on my MBP again once Mojave setup has completed on my MBA to see if it’ll boot my MBP at that point.

Edit: did not boot the MBP even though it will boot the MBA. Very weird.
 
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Check your USB-C to USB-C cable. I had the same problem after installing MacOS 10.14 and noticed that my original Samsung SSD T3 cable was broken. Tried another and now I am typing this in Safari 12.0 on Mojave installed on an external drive.
 
Frippefrippe said:
Check your USB-C to USB-C cable. I had the same problem after installing MacOS 10.14 and noticed that my original Samsung SSD T3 cable was broken. Tried another and now I am typing this in Safari 12.0 on Mojave installed on an external drive.
Click to expand...
I used the same USB-A cable that worked with the 2012 MBA just in case the USB-C cable was the issue. I also used a different cable + different external drive with the same result.

I am perplexed. I'm not sure what else to try.
 
I am having the exact same issue as PBG4 Dude, I'm also getting that circle and slash icon when booting Mojave from an external SSD. I'm also on a 2017 MacBook Pro. From reading this thread, my guess is it has to do something with USB-C type MacBooks. I tried booting while holding down Cmd + V to see what's going wrong. There I'm getting an
USBHostDevice::setConfigurationGated: compliance violation: failed to enable remote wake
error. Not sure what it means, but I guess we'll have to wait for the next beta and hope they fixed it there.
 
Good to know you and I are not alone! :)

I will try verbose boot and report back my results. I did notice my external USB enclosure light blinks in a way I've never seen it blink before when trying to boot Mojave.

(Hope this bug doesn't mess up your ice cream production.)
 
I get the same error on a 13" Mid 2014 MacBook Pro. It's a simple USB 3.0 flash drive: https://www.sandisk.com/home/usb-flash/ultra-fit-usb

EDIT: It's the drive. Try a different drive. I tried it on another external HDD partitioned in APFS and it works just fine. I've had issues with the Sandisk flash drive even when booting Ubuntu..
 
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sprintsucks said:
I get the same error on a 13" Mid 2014 MacBook Pro. It's a simple USB 3.0 flash drive: https://www.sandisk.com/home/usb-flash/ultra-fit-usb

EDIT: It's the drive. Try a different drive. I tried it on another external HDD partitioned in APFS and it works just fine. I've had issues with the Sandisk flash drive even when booting Ubuntu..
Click to expand...
I tried a different drive plus this SSD successfully booted Mojave when I connected it to my 2012 MBA.

Using verbose mode, the boot process hangs at “HID: shim level 2” on my MBP. Have no clue what that means. I think HID means Human Interface Device.
 
macOS hasn't been playing nicely with some external enclosures. It might be that the drive didn't get blessed during install. Please report it as a bug.
 
I have an external SSD connected to my MBPr (mid 2012). I installed Mojave on it without any problems. Prior to the install, the SSD was used for the High Sierra beta testing. Last macOS install before the Mojave installation was the first beta of 10.13.6. The SSD was already formatted in APFS. One thing I did notice, after the first boot into the installation process, the screen was blank for nearly 10 minutes. The SSD is connected to the MBP via USB 3.0 cable.
 
macsba said:
I have an external SSD connected to my MBPr (mid 2012). I installed Mojave on it without any problems. Prior to the install, the SSD was used for the High Sierra beta testing. Last macOS install before the Mojave installation was the first beta of 10.13.6. The SSD was already formatted in APFS. One thing I did notice, after the first boot into the installation process, the screen was blank for nearly 10 minutes. The SSD is connected to the MBP via USB 3.0 cable.
Click to expand...
that's good to know! I'll give it a try today.
 
TimothyR734 said:
do you have a external mouse connected to your MBP
Click to expand...
No, only power and the external drive. That’s why I find the HID mention weird.
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SoyCapitanSoyCapitan said:
macOS hasn't been playing nicely with some external enclosures. It might be that the drive didn't get blessed during install. Please report it as a bug.
Click to expand...
I tried two different ones. Even after making a bootable Mojave on my 2012 MBA it wasn’t recognized by my 2017 MBP. So it boots on my 2012 but not my 2017.

Planning to file a bug report today. Just wanted to give it a couple more tries to see if I could fix it, but still no joy.
 
For the record, I'm able to boot Mojave on a USB3 SSD.

My recipe:
1: High Sierra system on internal SSD block-cloned to external USB SSD
2: Ran "Install macOS 10.14 Beta.app" with the USB SSD as the target
3: There's no step 3

YMMV, but this worked perfectly fine on my Mid-2012 MacBook Air.
 
I was wondering if anybody got Mojave to run on an external drive with a USB-C type MacBook (i.e. a 2015 or newer MacBook, or a 2016 or newer MacBook Pro)?
 
I have a Mac mini with a USB 3 dock/SSD that ran High Serra and I just updated/installed Mojave over it. Didn't think anything about it until I saw this tread but it worked fine for me.

EDIT: Was HFS+ on High Serra and was reformatted to APFS with Mojave.
 
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Works fine for me, too. Installed it on the very first day beta 1 hit, on an external Crucial 128GB SSD in a USB 3 enclosure. Drive was formatted as HFS+, and was reformatted to APFS during installation.
 
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