Start-up trouble: screen shows circle with diagonal line through it

Discussion in 'Mac Pro' started by dee dee, Jul 9, 2008.

  1. dee dee macrumors newbie

    Jul 9, 2008
    Hi all,

    I'm a newbie here... My thanks in advance for an advice imparted in regards to the above....

    i.e: my G4 Quicksilver, running OSX10.3.9, is starting up with an odd screen: a circle with a line running diagonally through it, similar to a no smoking sign... I hope that makes sense!

    I have tried doing an archive and install but it hasn't fixed the problem, as i assumed it would...

    any ideas? what does this screen mean?

    any help very appreciated..

  2. matt321 macrumors member

    Oct 27, 2007
    Here is the apple link that tells you all about it:

    The cirlce with the diagonal is called a "prohibitory sign" indicating a critical file/folder is missing, not allowing you to boot up.

    My suggestion would be to do a clean install on a different hard drive, if you have one. Then migrate your user profile over.
  3. zmttoxics macrumors 65816


    May 20, 2008
    Aww... It sucks that your mac isn't feeling well. I would have to agree its the harddrive though. Odd that the archive install was successful yet it did not fix it. If you had an external firewire drive, you could do the install onto that and boot off of it. Then copy everything back off of the bad harddrive (is there a migration assistant in 10.3?).

    From there you can either live off of the firewire drive or change out the drives your self (or have someone do it for you).

    Good luck!
  4. dee dee thread starter macrumors newbie

    Jul 9, 2008
    Problem solved...


    thanks for getting this info for me.... so much appreciated...

    yep, it was a dud hard drive... though not my strt up drive... it was a secondary drive that has been playing up, to the point where it doesn't appear on the desktop anymore... tried fixing it in many ways using tech tool, but to no avail... its a goner!

    so i disconnected it and, either it was that, or the various tech tool suites used to fix volume probs, defrag, etc.. not sure which it was for sure, but i reckon it was the 2nd drive removal...

    anyway, no prohibited sign anymore, and seems to be running smoother...

    once again, thanks for responding with helpful info...

    all the best

  5. KaisMan macrumors newbie

    Feb 28, 2016
    Madison, WI
    So I hope this is the right place for this. Looks like an old thread.

    I have a 2009 Mac Pro. I desire to make multiple upgrades to this system. So I updated to El Capitan and did so on my Samsung EVO 500GB SSD. Then I partitioned half of it for Windows 7, now a Windows 10 bootcamp. This worked fine for me several weeks back.

    I then wanted SATA 3. And why not! So I installed a SATA 3 Port adapter in my third PCIe slot. The system booted fine then all of a sudden every time I turn it off and on again I get that darn Circle Slash/ Prohibitory Sign! I can get around it by holding Option and selecting Windows or Mac OS. They both boot fine from the boot menu. BUT why can I not let my system boot up without forcibly going to the boot menu. I am stumped after trying solve it on my own!

    Is this due to my SATA 3 PCIe port being seen as an "External Drive?"
    Is this due to both Mac OS and Windows booting from the same drive?

    Things I have done:
    1. All drives checked with first aid (No issues)
    2. Completely rebuilt El Capitan's boot files with an huge install file. No difference.
    3. PRAM Reset. Got me into MAC OS just two times and then Windows once (with now force to boot menu!)... then back to the Prohibitory symbol.
    4. Checked the Boot Readout behind the scenes. This is where the Prohibitory Symbol hits. (SEE ATTACHED PICTURE I TOOK)

    I will try to reconnect the SSD to the slow internal ports just to see what happens.

    Any advice? Thanks.

    Attached Files:

  6. flatfoot macrumors 65816

    Aug 11, 2009

    When booted into OS X, go to System Preferences–>Startup Disk and select your OS X partition there.

    This might fix it.

    Please report back.
  7. KaisMan macrumors newbie

    Feb 28, 2016
    Madison, WI
    That is how I switch to the other boot partition in Mac OS. The error comes after I select startup disk in Preferences as Windows partition then system reset. I try doing the same in Windows with the Bootcamp tray icon to send me to Mac OS again but same Prohibited Sign... It is only when I hold option and force the boot choice screen that I can get into the other Operating System.

    Another update:
    1. Today I pulled out the SATA 3 PCIe ports and just connected my (WIN/MAC) Startup drive to the first hard drive connectors on the motherboard. Then PRAM Reset. Same issues...
    2. I was worried that maybe my time machine backup drive was causing boot confusion in the system so I yanked that and still got the Prohibited sign.

    I am still able to boot no problem with holding option and choosing the operating system.

    That picture I uploaded in my previous post was the Verbose Mode readout when I get the Prohibited Sign. I can't make sense of it with google but maybe someone has an idea.

    So odd.
  8. flatfoot macrumors 65816

    Aug 11, 2009
    Maybe the mach-kernel replacement from the attached link does the trick. I'm pretty sure you shouldn't replace the mach_kernel on the disk you're currently boot from so boot from some other disk. – And make sure the mach_kernel is the correct OS X version!
    --- Post Merged, Mar 10, 2016 ---
    … or maybe reset PRAM again. It worked before and might again, hopefully permanently this time.

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