How to make an Emgency Boot Disc

Discussion in 'macOS' started by duggram, Jun 11, 2011.

  1. duggram macrumors 6502


    Apr 17, 2008
    How can I make a disk that I can put into my MBP and have it boot to my normal system?

    Last weekend I let the OS install about 7 updates. After installing them the computer would only boot to a gray screen with a "NO" symbol and the spinning image. I was trying to get to the airport so I grabbed what I thought was my install disk, but was really the app install disc and headed for the airport. Pressing C and booting to the app disc let the system start like normal.

    When I verified the disk permissions it found a problem with an ACL on launchd. Doing a repair fixed it. The next bootup was normal. But every time I booted after that I verified the disk and had to repair it again. BTW I don't know if the ACL on launchd is the root cause of the boot problems. At least I was able to boot up normal with this routine.

    Yesterday I booted up about 6 times with doing repairs and worked normally. So now I don't trust the OS to boot normal all the time, especially if I'm on a trip and won't be home for 5 days (happens every week) and don't have a boot disk of some type.

    Any help appreciated and yes I've researched this topic everywhere.
  2. duggram thread starter macrumors 6502


    Apr 17, 2008
    I think this issue is solved. I forgot that Apple gives free 90 day phone support. I called them and found out that one of the updates was a firmware/hardware update. This update may have caused some confusion for the OS. We did a disk repair and everything is now ok. I will carry my install disc with me for a few weeks tho.

    Sorry about the post but maybe someone else will benefit from it.
  3. iThinkergoiMac macrumors 68030

    Jan 20, 2010
    I have an external HDD that I carry with me anywhere I take my computer (well, whenever I take my computer bag with it, I've been known to grab just the computer if I know I won't need anything else). It's the old 160 GB drive that used to be in my MB. I erased it, and then created 2 partitions. The first partition is 8 GB, and is a bootable copy of my retail SL install disc. The 2nd partition is the rest of the HDD and is an installed copy of SL. This allows me to boot any Intel Mac with either the install disc or the installed OS. You can load up the installed OS with all kinds of diagnostic software and such things.

    This proved quite handy when I had to install SL on my in-laws' iMac but they didn't have an external drive to back everything up on. I was able to back everything up to the HDD and then install SL from it. It installs faster that way too.

    The nice thing is the drive is bus powered and it is in a very thin case, hardly bigger than the HDD itself. Probably the best use I've ever made of an extra HDD. Note that this will only work with a retail version of SL. It may indeed work for one of the grey discs, but you'll have the same limitation: it'll only work with your model, which may be all you need.
  4. duggram thread starter macrumors 6502


    Apr 17, 2008
    When I got this new MBP I replaced the HDD with an SSD. At the same time I put the original HDD in an encloser. Now how can I boot from that?
  5. brijazz macrumors 6502


    Jul 31, 2008
    Hold down the "Option" key while your system boots; you'll be presented with a list of all bootable volumes, and you can choose your enclosed drive from there.

    Also, you can book from your system DVD (the one that came with your Mac when you purchased it) by holding down "C" while booting. That's your emergency boot disc right there!

    Check out this link for other startup key combos:

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