iMac 14,1 2013 Ext HDD/OSX Bootable Issues

[SSpiro]

I had OSX set to boot from an external USB SSD. The iMac did this without issues for a good few years (3 years?). One day a few weeks ago, OSX wouldn't boot to my USB drive anymore, and i assumed it dead.

i tried to format it and reload OSX on it, and it wouldnt work, so I bought a new one. Unfortunately, i have the same problem with the new one. Disk utility can find it, and OSX install will start installation. When it gets to the point where it reboots, the machine reboots and reboots the internal drive and wont let me pick the external through boot manager to finish the install. It goes in this loop, and wont let me finish the install, nor boot to USB.

I am stumped on this one. Not sure what would have changed, and unsure on how to fix it.

 

[Fishrrman]

Will the iMac boot from the INTERNAL drive?

Will the iMac boot from INTERNET recovery?
(command-OPTION-R)

 

[Nguyen Duc Hieu]

I had OSX set to boot from an external USB SSD. The iMac did this without issues for a good few years (3 years?). One day a few weeks ago, OSX wouldn't boot to my USB drive anymore, and i assumed it dead.

i tried to format it and reload OSX on it, and it wouldnt work, so I bought a new one. Unfortunately, i have the same problem with the new one. Disk utility can find it, and OSX install will start installation. When it gets to the point where it reboots, the machine reboots and reboots the internal drive and wont let me pick the external through boot manager to finish the install. It goes in this loop, and wont let me finish the install, nor boot to USB.

I am stumped on this one. Not sure what would have changed, and unsure on how to fix it.

If a fresh install can't help, I guess it's hardware issue, though.

 

[SSpiro]

Will the iMac boot from the INTERNAL drive?

Will the iMac boot from INTERNET recovery?
(command-OPTION-R)

Yes to internal drive. Thats what its booting to now, which has OS running on it fine. I have not tried recovery yet. I can try that now and advise.

 

[SSpiro]

If a fresh install can't help, I guess it's hardware issue, though.

USB or logic board issue you think?

 

[Fishrrman]

OP wrote:
"Yes to internal drive. Thats what its booting to now"

If you boot from the internal drive, and then plug in the external SSD (try BOTH of them), does it mount on the desktop?

Can you run disk utility and do "first aid" on the external SSD?
What kind of report do you get?

If you can get the external drive to mount on the desktop, get the files you need off of it.
Then, try ERASING it.
Then, you could use either CarbonCopyCloner or SuperDuper to clone the contents of the internal drive to the external drive.
That may get it bootable again...

What version of the OS is on the internal drive?
What version of the OS is on the external drive?

What size is the internal drive?
What size is the external drive?

 

[Nguyen Duc Hieu]

USB or logic board issue you think?

If the "new one" you have tried and failed was a new USB enclosure with a new SSD inside, then the logic board, namely USB controller on the logic board is faulty.