External HD not recognized when moved internally

Discussion in 'Mac Pro' started by Doc69, Dec 10, 2013.

  1. Doc69 macrumors 6502

    Dec 21, 2005
    I just upgraded one of my data HDs in my Mac pro 5,1 from 3TB to 4TB. I formatted the new 4TB via FW800 and copied all the data to it. But now when I have moved it to one of the internal drive bays, to replace the 3TB drive, the Mac doesn't recognize it. It asks if I want to initialize it. So it shows up in Disk Utility but the partition is not there.

    Anyone know if this is normal or not? As far as I know, this should be possible. It would be strange if you had to format the drive when it's in the internal drive bay for it to work there.
  2. g4cube macrumors 6502a

    Apr 22, 2003
    Does your Mac support 4TB drives internally or require a special SATA driver?

    Your FireWire bridge in the external drive may take care of the 512-4K translation that these larger drives employ. Some USB and FireWire bridges do this for 4TB drives.
  3. Doc69 thread starter macrumors 6502

    Dec 21, 2005
    Yes, my Mac Pro supports 4TB drives. However, I think I figured it out, because when I took an internal drive an put it in the same FW800 dock (Seagate GoFlex), it didn't mount either.

    When I think of it, in the past, when I have moved internal drives externally, and vice versa, I have always used eSATA. So it's probably different when you use FW800. Anyway, I just bit the bullet and reformatted the 4TB inside the Mac Pro. So now I just have to copy the 3TB of data again, which was what I had hoped to avoid.
  4. costabunny macrumors 68020


    May 15, 2008
    Weymouth, UK
    Yep some external controllers are weird like that - The western digital MyBooks are the same. Annoying, but I guess thats how they intend to keep you buying their bespoke hardware for your drives :(

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