iMac slow boot - prohibited sign

Discussion in 'iMac' started by darkweather, Jun 19, 2016.

  1. darkweather, Jun 19, 2016
    Last edited: Jun 19, 2016

    darkweather macrumors regular

    darkweather

    Joined:
    Aug 8, 2013
    #1
    mac boot time is very slow with usb 3.0 external ssd. it was better months ago. here is etrecheck result:

    i add a video. :

    edit: disks
    /dev/disk0 (internal, physical):

    #: TYPE NAME SIZE IDENTIFIER

    0: GUID_partition_scheme *1.0 TB disk0

    1: EFI EFI 209.7 MB disk0s1

    2: Apple_HFS Macintosh HD 300.0 GB disk0s2

    3: Apple_Boot Recovery HD 650.0 MB disk0s3

    4: Apple_HFS HD2 699.2 GB disk0s4

    /dev/disk1 (external, physical):

    #: TYPE NAME SIZE IDENTIFIER

    0: GUID_partition_scheme *120.0 GB disk1

    1: EFI EFI 209.7 MB disk1s1

    2: Apple_HFS SSD 119.0 GB disk1s2

    3: Apple_Boot Recovery HD 784.2 MB disk1s3
     
  2. ZVH macrumors 6502

    Joined:
    Apr 14, 2012
    #2

    You shouldn't be seeing the prohibited sign during boot up. That means the system is unaware of what your boot drive is so it has to go to all the disks and figure out which one to boot from. That's adding about 20 seconds to your startup.

    You should be able to correct that by reseting the NVRAM which should clear that up:

    https://support.apple.com/en-us/HT204063

    If that doesn't help, try looking at reseting the SMC, but odds are it's the NVRAM. I've seen the exact same thing many times before after a drive swap and resetting the NVRAM did the trick. Here's a link for resetting the SMC if needed:

    https://support.apple.com/en-us/HT201295

    If non of that works, try this for more info on drive problems:

    http://scsc-online.com/Bad Hard Drive Signs and Symptoms.html

    I'd be willing to bet its nothing more than the needed NVRAM reset. Keep in mind if your USB port is version 2.0 instead of 3.0 it will be bottlenecked by the slower I/O interface and it will never be as fast as SATA II or III internal interface.
     
  3. darkweather thread starter macrumors regular

    darkweather

    Joined:
    Aug 8, 2013
    #3
    i did nvram and smc reset but nothing changed.
     
  4. keysofanxiety macrumors 604

    keysofanxiety

    Joined:
    Nov 23, 2011
    #4
    Hold Alt on startup. Select the drive you want to boot to by using the arrow keys. Hold Ctrl and you will see the arrow icon change. Then press Enter. This will change your default boot disk.

    Any better?
     
  5. Weaselboy Moderator

    Weaselboy

    Staff Member

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    Jan 23, 2005
    Location:
    California
    #5
    I think what is happening is you don't have a startup disk identified, so when the system starts it has to hunt all around for all available drives before it finds the boot drive. To fix it, startup then go to System Preferences and in the Startup Disk pane select your external SSD as the boot drive.
     
  6. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #6
    The NVRAM reset will also un-set the default startup disk. After the NVRAM reset, be sure to go in to System Preferences/Startup Disk, and make sure that your external drive is the one selected. Click the padlock on that pane to unlock the settings.

    Finally, TRIM might be an issue that complicates your symptoms. Macs don't support TRIM over a USB connection - even if you think TRIM is enabled, it will be only for the internal storage bus, or SSDs connected through Thunderbolt.
     
  7. darkweather thread starter macrumors regular

    darkweather

    Joined:
    Aug 8, 2013
    #7
    thank you all for the help. i think the problem was "The NVRAM reset will also un-set the default startup disk". that's ok now.
     
  8. darkweather, Jun 22, 2016
    Last edited: Jun 24, 2016

    darkweather thread starter macrumors regular

    darkweather

    Joined:
    Aug 8, 2013
    #8
    i thought it was solved but today it happend again (the prohibited sign). i'm sure that the external SSD is set as the boot drive.
    [​IMG]
     
  9. Weaselboy Moderator

    Weaselboy

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    California
    #9
    I can't read your text there, but normally the selected boot drive is highlighted like this. Are you sure the SSD is selected?

    Screen Shot 2016-06-22 at 8.53.59 AM.png
     
  10. darkweather thread starter macrumors regular

    darkweather

    Joined:
    Aug 8, 2013
    #10
    yes i'm sure, ssd is selected.
     
  11. redheeler macrumors 603

    redheeler

    Joined:
    Oct 17, 2014
    #11
    The OP's screenshot shows the SSD is set as the default boot drive because otherwise the icon would be slightly transparent like the one next to it. The label only becomes highlighted once the pane is unlocked like in your screenshot.
     
  12. Weaselboy, Jun 22, 2016
    Last edited: Jun 22, 2016

    Weaselboy Moderator

    Weaselboy

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    #12
    Ah... gotcha thanks. Never noticed the difference.

    OP> I'm kinda out of ideas here short of either the SSD or enclosure being bad.
     
  13. MacRobert10 macrumors 6502

    Joined:
    Nov 24, 2012
    #13
    Just a guess, but could it be possible that the USB device is port powered and starts off in low power mode and the system has to kick it into high power mode to start the unit up? If that's the case and the unit has a provision to be externally powered then supplying external power to the unit may stop that from happening.

    This is a guess, but it might be worth checking out. Here's a link to USB power:
    https://en.wikipedia.org/wiki/USB#Power

    Go down to the power section in that article if interested.

    Good luck.
     
  14. grahamperrin macrumors 601

    grahamperrin

    Joined:
    Jun 8, 2007
    #14
    Suspect a physical problem with the drive, or an HFS Plus file system inconsistency (which may be not detectable by Disk Utility).
     
  15. darkweather thread starter macrumors regular

    darkweather

    Joined:
    Aug 8, 2013
    #15
    i don't not exactly remember but i think this problem has begun with early versions of yosemite (10.10.x). before there wasn't a problem like that.
    and one more thing (that causes i mark the thread as resolved) when i (re)select ssd from system preferences (startup disk) and restart system, that sign doesn't appear.
    so i don't think this is a physcal problem. there must be some setting to solve this.
     
  16. darkweather thread starter macrumors regular

    darkweather

    Joined:
    Aug 8, 2013
    #16
    here is the screen capture of the verbose mode (cmd+V) during boot:
    [​IMG]
     
  17. JohnDS, Jun 23, 2016
    Last edited: Jun 23, 2016

    JohnDS macrumors 65816

    Joined:
    Oct 25, 2015
    #17
    How old is the iMac? It may be that the PRAM battery is dying. (Oops, sorry, see yours is a 2012 and it doesn't have PRAM battery, so please ignore this post.)
     
  18. darkweather thread starter macrumors regular

    darkweather

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    Aug 8, 2013
  19. maflynn Moderator

    maflynn

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    Boston
    #19
    Did you try running off the internal drive and not the external SSD to see if the symptoms reappear?
     
  20. darkweather thread starter macrumors regular

    darkweather

    Joined:
    Aug 8, 2013
    #20
    I formatted SSD via a Windows pc. Then download the El capitan and installed.

    Nothing changed...
    --- Post Merged, Jun 24, 2016 ---
    Withour SSD there is no such a problem. Internal drive boots normally (if we don't consider the very very slowness of the hdd)
     
  21. maflynn Moderator

    maflynn

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    May 3, 2009
    Location:
    Boston
    #21
    So I wonder then if the issue is related to the external drive, or USB port. Did you try a different port, and if possible, try the external drive on another mac?

    It was asked above, but I didn't see an answer, did you try to boot the mac up with holding the option key and then selecting the external drive - does the issue occur when you try that?
     
  22. darkweather, Jun 24, 2016
    Last edited: Jun 24, 2016

    darkweather thread starter macrumors regular

    darkweather

    Joined:
    Aug 8, 2013
    #22
    Now i'm loading time machine backup. After that I will try it and write again.
    --- Post Merged, Jun 24, 2016 ---
    i tried it two times; answer is no. when i boot the mac up with holding the option key and then selecting the external drive the issue doesn't occur, apple logo is instantly seen and mac boots up speedly.

    so, what could be the problem?
     
  23. hfg macrumors 68040

    hfg

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    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #23


    This could be a problem ... did you format it as a Windows FAT volume?
     
  24. JohnDS, Jun 24, 2016
    Last edited: Jun 24, 2016

    JohnDS macrumors 65816

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    Oct 25, 2015
    #24
    What hfg is getting at is that for a Mac volume to be bootable, it has to be formatted as Apple Extended Format (Journalled), not FAT, or ExFat or NTFS. Without special third party Windows software, like MacDrive for instance, you cannot format a drive as a Mac volume from Windows. You have to use a Mac to do that.
     
  25. hfg macrumors 68040

    hfg

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    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #25
    That was what I was getting at ... the OP couldn't have formatted it as OS X from a Windows PC, but he could download to a FAT volume not realizing there would be a problem later on. At some point he has to format the external drive for OS X before trying to use it as a boot volume.
     

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