My OS X Partition Shows Up as "EFI Boot," and Now I Can't Get In!

Discussion in 'macOS' started by ardesigns, Jun 5, 2009.

  1. ardesigns macrumors member

    Joined:
    Mar 20, 2008
    #1
    Hi guys. I have 2 partitions on my MacBook drive. One is OS X Leopard, and the other is a Windows XP Bootcamp Partition (FAT32). When I made the Bootcamp partition, I cloned up my OS X partition to a USB drive (using Carbon Copy Cloner), replaced the OS X partition with the clone (to defragment it), and then partitioned it using Bootcamp. I decided I wanted a larger Windows XP Bootcamp Partition, and so I removed the partition using Bootcamp, recloned and replaced the OS X partition with the recloned backup (to defragment it, once again), and then used Bootcamp again to partition it, this time with a larger partition size.

    The first time I partitioned it, everything worked great. Ever since the second time, though, when I hold option during startup to change boot volumes, the volume that once said "Macintosh HD" now says "EFI Boot." Also, my OS X partition is no longer the default partition, and when I lookt at the Startup Disk in the System Preferences, my OS X partition is not listed among them. This is the same when I look at the "Startup Disk" preferences on the Windows XP partition, using the Boot Camp application, and when I click "Startup in Mac OS X," I get the error: "Could Not Locate Mac OS X Volume."

    I had been ignoring the problem, simply holding option on startup and choosing the "EFI Boot" volume. This was working fine until today, when I finally came around to updating OS X. I ran Software Update, which told me I had to restart my computer. When I did, it went through the whole updating progress bar screen for a while, and then restarted the computer. When the computer restarted, it restarted in Windows XP, so I shut down the computer, booted it up, and held option. I chose "EFI Boot" when I was given the choice, and it started booting to my OS X partition. About a minute or two after I chose "EFI Boot," the computer unexpectedly rebooted into Windows XP again. I restarted the computer, again holding option and choosing "EFI Boot," and again it unexpectedly restarted.

    What happened?! How can I get back into my OS X partition? Is there a way I can clone my OS X partition and replace it like I've done in the past? (Note: I have MacDrive 7, and have seen an option for backing up drives on there in the past, but have never used it.) Why is my OS X partition showing up as "EFI Boot"?

    Thanks,
    ARDesigns
     
  2. ardesigns thread starter macrumors member

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    Mar 20, 2008
  3. chas0001 macrumors 6502a

    chas0001

    Joined:
    Sep 18, 2006
    Location:
    Alicante, SPAIN
    #3
    If you installed the 10.5.7 update the computer will automatically reboot at least twice (as part of the installation process). It will reboot into windows each time because that volume must be the startup volume.


    It looks like your partitions have got muddled somehow. Why don't boot from the install DVD and change the startup volume to OS X and try and repair the whole disk using disk utility.
     
  4. SydneyDev macrumors 6502

    Joined:
    Sep 15, 2008
    #4
    I think the EFI Boot partition is a small hidden partition that the Mac uses only when doing EFI updates. It is there all the time, Disk Utility just doesn't show it.

    It sounds like somehow, in the past, your Mac got mixed up and started thinking the main OS X partition was the EFI partition. Everything still worked, but when you did the recent update, the updater saved the new firmware on the EFI partition, like it is supposed to, except in your case it was your main partition, so the EFI files may have overwritten some of your OS files, causing the OS to no longer work. This is just a guess.
     
  5. ardesigns thread starter macrumors member

    Joined:
    Mar 20, 2008
    #5
    So if I boot from the install CD, repair the permissions on all disks, and set the Mac partition as the default (if that's possible) the problem might be solved?

    I'll try it out and tell you how it goes.

    Thanks!
     
  6. chas0001 macrumors 6502a

    chas0001

    Joined:
    Sep 18, 2006
    Location:
    Alicante, SPAIN
    #6
    As SydneyDev has stated, looks like somehow the hidden partition is no longer hidden. Using disk utility is the first step to trying to resolve most problems. Its hard to say that it will solve it. The best thing to do is see if you can see the 'real' OS X partition and try and repair it.

    A disk with OS X and Windows installed will usually look something like this :

    /dev/disk0
    #: TYPE NAME SIZE IDENTIFIER
    0: GUID_partition_scheme *1.4 Ti disk0
    1: EFI 200.0 Mi disk0s1
    2: Apple_HFS Macintosh HD 900.2 Gi disk0s2
    3: Microsoft Basic Data WindowsVista 496.7 Gi disk0s3

    3 partitions : EFI, Macintosh HD and Windows. The EFI partition should be hidden.
     
  7. ardesigns thread starter macrumors member

    Joined:
    Mar 20, 2008
    #7
    The only thing I worry about is that if I unhide the OS X partition and hide the EFI one, will the OS X partition only have the saved data that it had when I first partitioned the computer?

    Thanks!
     
  8. ardesigns thread starter macrumors member

    Joined:
    Mar 20, 2008
    #8
    I used the OS X Install disk to "repair permissions" and "repair disk" on the OS X partition. I then restarted, held Option, and the OS X partition is now labeled "Macintosh HD." Good so far. Then, I booted to "Macintosh HD," and the swirley loading animation came up and stayed there for 2 - 3 hours, at which I time I shut down the computer, restarted (it restarted to the Windows partition first, so I had to restart again and hold option, and select the OS X Partition) and it did the same thing.

    While the "EFI" thing is now gone, why won't it start up in OS X?

    Thanks again!
     
  9. chas0001 macrumors 6502a

    chas0001

    Joined:
    Sep 18, 2006
    Location:
    Alicante, SPAIN
    #9
    Perhaps some of the system files have got corrupted.

    Perhaps your best option is to boot again from the OS X Installation DVD and do an 'ARCHIVE and INSTALL' onto your Macintosh HD, making sure that you check the boxes for preserving user accounts and network settings.

    Check this out : http://www.youtube.com/watch?v=9y1Ki8BMRZw (its the same process on all Macs)

    This type of installation will preserve your user data (you may need to enter serial numbers again for some pieces of software and reinstall web plugins) but will re-install all the system files. After the installation you will need to perform a software update (maybe a couple of times).

    Does anybody else have any suggestions?
     
  10. Semiopaque macrumors regular

    Joined:
    Oct 7, 2008
    #10
    I'm kinda guessing here too, but you might have created an additional boot partition that no longer points to loading OS X (possibly during cloning and the update process updated the wrong partition or something?). Since you can boot into XP, go to Computer Management in XP and check Disk Management and see how many partitions and what sizes they are. I forget how XP sees GPTs so you might see some unallocated or even Raw areas of the disk that actually aren't (your OS X partition should show up as unallocated and be noticeable by its size).

    If I'm recalling correctly, you should only have 4 partitions 1 about 200 MB and one about 128 MB and two others are your XP and OS X partitions of much larger sizes. If you have more partitions or the partitions are larger (or not there at all), that might be a starting point for fixing it.
     
  11. ardesigns thread starter macrumors member

    Joined:
    Mar 20, 2008
    #11
    Hi guys. Thanks so much for the help you've given me so far! I just checked my partitions in XP (as suggested by Semiopague). It says I have 3 partitions, one is 200 MB, another is 129 MB, another is 80.88 GB (OS X), and the last one is 30.59 GB (Windows). I'm not sure what to make of that, or if that means anything is wrong...

    As Chas0001 suggested, I'll try archiving and installing with the OS X Install CD in a little bit and tell you how it goes.

    Thanks again,
    ARDesigns
     
  12. Semiopaque macrumors regular

    Joined:
    Oct 7, 2008
    #12
    The partitions look ok so...have you tried holding down the 'X' when booting and forcing a start-up in OS X? It may allow you to go through all the updates and maybe (?) fix it.
     

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