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gpezzino

macrumors member
Original poster
Mar 27, 2008
36
0
Late 2013 iMac i7 3.5GHz. I created a clone on an external Seagate UBS-3 drive. The cloned external drive will not boot using a USB-3 cable, but it will using a USB-2 cable. The drive works fine as a USB-3 drive if I boot from the internal drive.

Is there an incompatibility between these iMac models and external USB-e drives, as far as a boot drive goes?

Thank you!
 
Mavericks, on a 2010 MBP, 27" 2009 iMac & 15" 2013 MBP. No problem on any of them.

Thank you. ANyone with a 2013 iMac i7 being able to boot from an external UBS-3 drive? I know they are **supposed** to work, but I would like a direct report. Thanks!
 
Thank you. ANyone with a 2013 iMac i7 being able to boot from an external UBS-3 drive? I know they are **supposed** to work, but I would like a direct report. Thanks!

Yeah, I can boot from mine, no sweat. (3.5GHz i7, 32GB RAM, 512GB SSD, 4GB GTX780M).

I think you should do a clean install and check whether the problem still persists or not.
 
Update

Yeah, I can boot from mine, no sweat. (3.5GHz i7, 32GB RAM, 512GB SSD, 4GB GTX780M).

I think you should do a clean install and check whether the problem still persists or not.

It turns out the problem is drive-specific. I created a clone on a different drive (Toshiba , USB-3) and it worked. The drive in trouble is a Seagate 3TB, the one that works a 2TB, I am not sure if that makes a difference.

As I said, the Seagate will boot using a USB-2 cable, so the problem is not with the format or file system.
 
Have you tried using different USB 3 cables?

What about different USB ports on the Mac?

I can confirm that the problem is the external Seagate 3TB drive, which does not boot on USB-3. An external WD 2TB clone boots regularly on USB-3. The Seagate WILL boot with a USB-2 cable and will work regularly with a USB-3 cable, except that it will not boot. Something to do with the extra capacity, perhaps?

Anyway, I have swapped drives, the Seagate is now my Time Machine drive and the WD my clone.

Thank you all for your advice!
 
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