I have a 2TB Hitachi Backup drive, and a 1TB Verbatim Portable drive, both are USB 3, and when they are connected and the iMac is switched off, it will not boot until I remove the drive.
How can I leave the 2TB drive connected and power up the iMac ?
The 2TB drive was purchased to be a Time Machine backup drive.
Thanks
iMac, Mac OS X (10.7.3), 3.4GHz Intel Core i7 - 8GB
Are you using USB 2 or USB3/2 cables?
As each drive has a proprietry USB3 end to the drive, I can only use the supplied cable.
Take the drive back, your Mac can't use USB 3, however it's supposed to be backwards compatible with USB 2, so what the heck right?
Drive is a problem or the Mac?
Get USB 2/1 or Firewire 800/ USB 2/1
Also Mac's don't like large size port powered drives all that much, power drain.
The drives work fine on any Windows PC, with USB 2 ports. They work fine on the iMac when it's booted. The Hitachi and Verbatim drives just will not allow the Mac to boot.
As they both work OK with a PC, I think it's an Apple problem to resolve. It's a pain to keep removing them when I need to boot up the PC.
The Hitachi has it's own Power Supply, so the power drain on the port is not relevant here. It is recognised as a Time Machine drive, so it shoudl act like a permanent attached drive.
The Verbatim drive is the same size as the iMac.
I will log a formal support ticket with Apple later this week if there are not suggested solutions coming from this community.
Apple doesn't support USB 3, they are promoting Thunderbolt and just like when they promoted Firewire, they didn't jump on the USB 2 bandwagon until a few years later to give it a chance.
USB 3.0 driver hasn't been released for Macs yet.
So given the drives are backwards compatible to USB 2.0 ports, why is the iMac and Lion not handling them correctly ? Sounds to me like a bug in OSX.
It's not about the lack of USB3 drivers or support for USB3, because the ports are USB 2.0 on the iMac.
I will need to do a final test with a USB 2 only portable drive and see if that will stop the iMac from booting also.
https://discussions.apple.com/docs/DOC-3003 explains the formatting external hard drives have to be to be usable on a Mac.
The Hitachi disk was originally formatted in NTFS, and would not allow the iMac to boot, but when booted could read but not write to the disk..
When it was re-formatted in FAT, it still would not allow the iMac to boot, but could read and write to the drive.
I'm not sure its a drive format issue at this moment in time, more a boot squence or expectation of a USB being bootable.
UKCobra wrote:
As each drive has a proprietry USB3 end to the drive, I can only use the supplied cable.
You can purchase alternative 3rd party cables
Time Machine drives are not bootable, only clones and direct installation from Apple operating system CDs.
As it stops the drive from booting, I have not configured it as a TM backup drive yet. I need to fix the fundamental issue of it stopping the machine from booting !
How and Why ? and What benefit would that give me ?
Each end of the drive is unique to the manufacturer. The Hitachi drive connector and Verbatim one are different, but the end to the iMac is a regular USB connector.
The drives do transfer data via this cable. It works.
What does not work, is that when the iMac is powered off, if a USB 3 drive is connected, the iMac will not boot up. Removing the cable/drive, will let the iMac boot, I then have to re-connect the drive. OSX will recognise the drive and all is good.
UKCobra wrote:
How and Why ? and What benefit would that give me ?
Hard to tell whether your cables contribute to the no boot, especially without trying.
I think it's unlikely a third pary one will solve it, when a Hitachi and Verbatim one gives the same issue.
I don;t even think there are third party USB 3 cables, as the ports on the drive are unique and different.
Unable to Boot when USB 3 Drive attached
