What is EFI?

Question

Level 2

279 points

What is EFI?

When I start my MacBookPro 2.16 10.5.7 holding the option key to choose an external drive to start up with my external drive is labeled EFI and not the the name I gave it. I've started up from external drives a lot of times and always has been named the name I gave it.
Is this the sign of a problem?
Thanks,
BobM

MBP C2D 15", Ibook,iMacG5, iMac Intel, G4 867 oh yeah and an iPhone, Mac OS X (10.5.4)

Posted on Jun 13, 2009 12:41 PM

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Answer 1

nerowolfe

Level 6

13,090 points

Jun 13, 2009 12:45 PM in response to B BM

EFI, extensible firmware interface is the new "BIOS"
http://en.wikipedia.org/wiki/ExtensibleFirmwareInterface
Why your HD is named EFI, I don't know. Is it acting up or anything?
What format is it? What's on it?
Did you ever install rEFIt or any other boot software for running other OSs?

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Answer 2

Kappy

Level 10

362,007 points

Jun 13, 2009 12:46 PM in response to B BM

See Extensible Firmware Interface. If you have cloned an OS X installer DVD to your external drive, then it will appear in the Boot Manager screen with the EFI label. If you originally partition and format a drive but do not give it a name until after it's mounted on the Desktop this will sometimes result in that label in the Boot Manager. It is harmless and not a sign of a problem.

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Answer 3

B BM Author

Level 2

279 points

Jun 13, 2009 1:04 PM in response to Kappy

Thanks to you both for your replies. I have cloned a system onto the drive but it never changed the name before. It seems to be running fine. I also changed the drive name but do not remember if I named the drive when partitioned.
Thanks again to you both.
BobM

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Answer 4

nerowolfe

Level 6

13,090 points

Jun 13, 2009 1:26 PM in response to B BM

As Kappy mentioned, one of the two cloners, CCC or SuperDuper! sometimes renamed the drive.
i suspect it's tied in with the drive being bootable in the EFI environment. A minor glitch with the clone software.

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