Joe M21
Level 1 (38 points)
Mac OS X

Q: Mac will not restart, but will boot

Strange problem with my Mac Pro running Lion 10.7.4 (although problem dates back to at least 10.7.3).

 

The machine will not restart. When I attempt a "restart," everything seems to shut down properly. When trying to start back up, the machine hangs at the gray screen. I have left it there for a long time and nothing happens.

 

However, I then force a shut-down by holding the power button for a few seconds. After that, the machine will start up properly. Again, a "cold" start works perfectly fine. Only a "restart" causes a problem and will always hang at the gray screen (no logo - nothing).

 

 

This is the only way I can restart my machine. Any ideas on what is going on or how to fix it?

Mac Pro, Mac OS X (10.7.4), 20GB Ram

Posted on May 15, 2012 6:12 AM

by softwater,Solvedanswer
softwater softwater
Level 5 (5,387 points)
Mac OS X
A:

Boot your mac in Safe Mode

 

http://support.apple.com/kb/HT1455

 

The boot will take longer than usual, and you should see 'safe mode' in red indicated in the top right corner of the screen as its booting up.

 

When its finished, hit 'restart' as usual.

 

Same problem?

Posted on May 15, 2012 6:22 AM

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Joe M21

Q: Mac will not restart, but will boot

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  • Helpful answers

  • by softwater,Solvedanswer

    softwater softwater May 15, 2012 6:22 AM in response to Joe M21
    Level 5 (5,387 points)
    Mac OS X
    May 15, 2012 6:22 AM in response to Joe M21

    Boot your mac in Safe Mode

     

    http://support.apple.com/kb/HT1455

     

    The boot will take longer than usual, and you should see 'safe mode' in red indicated in the top right corner of the screen as its booting up.

     

    When its finished, hit 'restart' as usual.

     

    Same problem?

  • by ds store,

    ds store ds store May 15, 2012 6:54 AM in response to Joe M21
    Level 7 (30,395 points)
    May 15, 2012 6:54 AM in response to Joe M21

    See #7 "Gray Screen" here

     

    Step by Step to fix your Mac

  • by keg55,

    keg55 keg55 May 15, 2012 7:53 AM in response to ds store
    Level 6 (8,368 points)
    Mac OS X
    May 15, 2012 7:53 AM in response to ds store

    Nice write up, ds store.

  • by Joe M21,

    Joe M21 Joe M21 May 23, 2012 6:37 PM in response to softwater
    Level 1 (38 points)
    Mac OS X
    May 23, 2012 6:37 PM in response to softwater

    The safe boot followed by a restart solved it. Very strange. No idea why a safeboot would fix anything, but it appraently did.

     

    Thanks,

  • by softwater,

    softwater softwater May 24, 2012 11:28 PM in response to Joe M21
    Level 5 (5,387 points)
    Mac OS X
    May 24, 2012 11:28 PM in response to Joe M21

    Joe M21 wrote:

     

    No idea why a safeboot would fix anything, but it appraently did.

     

     

     

    From the Apple Support doc:

     

    Starting up into Safe Mode does several things:

    • It forces a directory check of the startup volume.

     

    • It loads only required kernel extensions (some of the items in /System/Library/Extensions).

     

    • In Mac OS X v10.3.9 or earlier, Safe Mode runs only Apple-installed startup items (such items may be installed either in /Library/StartupItems or in /System/Library/StartupItems; these are different than user-selected account login items).

     

    • It disables all fonts other than those in /System/Library/Fonts (Mac OS X v10.4 or later).

     

    • It moves to the Trash all font caches normally stored in /Library/Caches/com.apple.ATS/(uid)/ , where (uid) is a user ID number such as 501 (Mac OS X v10.4 or later).

     

    • It disables all startup items and login items (Mac OS X v10.4 or later).

     

    • Mac OS X v10.5.6 or later: A Safe Boot deletes the dynamic loader shared cache at (/var/db/dyld/). A cache with issues may cause a blue screen on startup, particularly after a Software Update. Restarting normally recreates this cache.


    Taken together, these changes can help resolve software or directory issues that may exist on the startup volume.

  • by hohohmm,

    hohohmm hohohmm Jan 1, 2014 8:08 PM in response to Joe M21
    Level 1 (0 points)
    Jan 1, 2014 8:08 PM in response to Joe M21

    I had the exact same problem. It turns out that it's caused by the external USB hub connected to the laptop. I powered the hub off then on after the computer is shutdown, and replugged it into the USB port. Then the problem was gone.

  • by Gabriel (Andreaux),

    Gabriel (Andreaux) Gabriel (Andreaux) Sep 5, 2016 5:19 PM in response to Joe M21
    Level 1 (4 points)
    Sep 5, 2016 5:19 PM in response to Joe M21

    Do you have a CTO Mac Pro 1,1? If so, I may have a solution for you.

     

    I fixed my CTO Mac Pro 1,1 having the exact same issues. It turned out that the firmware these machines shipped with is buggy (or got buggy along the way, I don't know). But I can 100% safely restart the Mac Pro now.

     

    Please confirm in System Profiler that you have a ROM version of: MP11.005D.B00

     

    Let me know.