ron.durst

Q: Prohibitory Sign! Nothing but the prohibitory sign!

Just a disclaimer, I'm not very smart when it comes to computers so please bare with me. I normally deal with windows so this whole Mac thing is new to me also.

 

I just recently bought a mac pro tower from someone. It powers up, shows the apple symbol, and then goes to the prohibitory sign. I've looked this up for hours and they all say to go into disk utilities and all of that stuff. Command R. Command, option. R. I've done it all and it all just goes back to that sign. Holding Option down will bring me to where it will let me select a drive to boot from but of course the only drive is the main ssd which is apparently corrupted. 

 

I've looked into making a bootable flash drive but cant seem to find any way to do it from a windows pc. I do not have another Mac around.

 

I am desperate! Thanks for your help.

Mac Pro

Posted on Sep 12, 2016 5:59 PM

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Q: Prohibitory Sign! Nothing but the prohibitory sign!

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  • by Kappy,

    Kappy Kappy Sep 12, 2016 6:15 PM in response to ron.durst
    Level 10 (271,174 points)
    Desktops
    Sep 12, 2016 6:15 PM in response to ron.durst

    Mac OS X- Gray screen or prohibitory sign appears during startup

     

    We will need to know the exact model you have to help further. You cannot create a bootable flash drive unless you have a saved copy of an OS X Installer Application. Nothing can be done on a Windows PC.

     

    If your machine is a late enough model (2011 or later) to allow Network Recovery, then you can try the following:

    Network Install of El Capitan

     

    1. Restart the computer. Immediately after the chime hold down the Command-Option-R keys until a globe appears.
    2. The Utility Menu will appear in from 5-20 minutes. Be patient.
    3. Select Disk Utility and click on the Continue button.
    4. When Disk Utility loads select the drive (usually, the out-dented entry) from the side list.
    5. Click on the Partition tab in Disk Utility's main window. A panel will drop down.
    6. Set the partition scheme to GUID.
    7. Set the Format type to Mac OS Extended (Journaled.)
    8. Click on the Apply button, then click on the Done button when it activates.
    9. Quit Disk Utility and return to the Utility Menu.
    10. Select Reinstall OS X and click on the Continue button.

     

    This should install the version of OS X that was pre-installed when the computer was new.

  • by ron.durst,

    ron.durst ron.durst Sep 12, 2016 6:21 PM in response to Kappy
    Level 1 (4 points)
    Desktops
    Sep 12, 2016 6:21 PM in response to Kappy

    How do I find the exact model? Is it on the pc somewhere? I'm not seeing it.

     

    Does the Ethernet cable need to be plugged in for it to even go to internet recovery mode?

  • by Kappy,

    Kappy Kappy Sep 12, 2016 9:57 PM in response to ron.durst
    Level 10 (271,174 points)
    Desktops
    Sep 12, 2016 9:57 PM in response to ron.durst

    Open About This Mac under the Apple menu or get the Model ID using System Information: To find the model identifier open System Profiler in the Utilities folder. It's displayed in the panel on the right.

     

    You need an Internet connection. It can be either wired or wireless.

  • by lllaass,

    lllaass lllaass Sep 13, 2016 12:53 AM in response to ron.durst
    Level 10 (188,994 points)
    Desktops
    Sep 13, 2016 12:53 AM in response to ron.durst

    To my knowledge of the Mac Pros, only the 2013 Mac Pro black cylinder has Internet Recover.

  • by ron.durst,

    ron.durst ron.durst Sep 13, 2016 5:43 AM in response to Kappy
    Level 1 (4 points)
    Desktops
    Sep 13, 2016 5:43 AM in response to Kappy

    Haha. If i could do all of that, I wouldn't have posted the original post.