Prohibitory symbol on startup mac

Thread Tools Show Printable Version. I also updated my G4's firmware to 4. All seemed fine, the firmware update was successful, the new drives were mounting, this was all early this afternoon.


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What does this mean? So I powered down the computer and restarted holding "option" so I could choose what drive to boot off of. I selected the OSX partition on my new drive and it booted right up. I went through the whole process again to the same exact results. Anybody know what the problem is? I really want to get this figured out so I can install my new processor and get back to work. Any help would be appreciated. Posts I probably know what it is Jason, I never did see it happening and I do not have Gigadesign upgrade, but we have similar machines.

I have a theory, what it is and hopefully can help you out.

FiX! Prohibition Sign MacBook (How to set up new IOS MacBook)

Eventually I will call you. Please contact card manufacturer's support. I still have my original system drive stock ATA installed and am able to boot and reboot off it but not with the new Seagate. I ran disk utility and verified and repaired permissions on the new hdd. Disk utility showed a bunch of stuff wrong when I checked the permissions but said it repaired them.

But it's still doing the same thing. The suspense is killing me. Originally Posted by sonikbliss.

You See a Prohibitory Sign When Starting Mountain Lion

That was easy. Perhaps there was a glitch while my Mac was initially looking for a bootable drive. These things happen. I had heard that Apple had released versions of Mojave newer than the one I initially installed. I had been promoted several times by Mojave to update, but ignored those prompts for severals weeks. Earlier today, I decided it was time for me to be running the latest version of Mojave beta.

The About This Mac window opened with the Overview tab highlighted. I then clicked on Software Update… highlighted in red :. I clicked the Update Now button highlighted in red :. I clicked the Install Now button highlighted in red :. I pressed the power button until my MacBook Pro powered down. I used the Startup Manager as described above and at the link , holding the option key down as soon as I heard the Apple chime.

I selected the one named macOS Installer :. Then it showed me progress as it performed the update:. The update process may take awhile. When the progress bar reaches the end of the estimated processing time marker, the screen may go black. In all cases, your Mac seems to be stuck. There are no unusual noises, such as disk access, optical drive spin up or down, or excessive fan noise; just a Mac that won't continue to the login screen or the desktop.

Another startup problem that's mistaken for the gray screen issue is a gray screen with a folder icon and a flashing question mark. That's a separate problem, which is easy to fix with the help of our troubleshooting guide.


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  4. Disconnect all external peripherals , and keep them removed for the duration of these steps unless otherwise noted. Don't disconnect the keyboard , mouse, or display. If your keyboard or mouse is connected through a USB hub, bypass the hub by plugging the keyboard and mouse directly into your Mac for these tests. One of the most common problems that can cause the gray screen issue is a bad peripheral or peripheral cable.

    Troubleshooting Mac startup problems

    When a bad peripheral is plugged into your Mac, it can prevent it from continuing the startup sequence, and cause it to stall while it waits for the peripheral to respond to a command. The most common form of this is when a bad peripheral or its cable causes one of the signaling pins on one of Mac's ports to get stuck in one condition set high, set low, or shorted out to ground or positive voltage. Any of these conditions can cause your Mac to freeze during the startup process. If your Mac starts back up without issue, then you'll know that it's a problem with a peripheral.

    Mac Startup Prohibitory Sign : Get Corrupted Deleted Mac Data Recovered

    You'll need to shut your Mac back down, reconnect one peripheral, and then restart your Mac. Continue this process of reconnecting one peripheral at a time and then restarting your Mac until you find the bad peripheral. Remember that the problem can also be a bad cable, so if you plug a peripheral back in and it causes the gray screen issue, try the peripheral with a new cable before you replace the peripheral.

    Swap your mouse and keyboard with a known good pair, and then restart your Mac.

    Prohibitory symbol

    If you don't have spares, just disconnect them and restart by pressing and holding the power key. If your Mac gets to the login screen or desktop, then you'll need to determine whether the problem is the mouse or the keyboard. Try plugging in one at a time and then restarting to confirm. Start your Mac using the Safe Boot process if no peripheral or cable appears to be at fault.

    Prohibitory symbol on startup

    To do that, first disconnect all of the peripherals, except the mouse and keyboard. During the Safe Boot, your Mac performs a directory check of your startup drive. If the drive directory is intact, the OS continues the startup process by loading only the minimum number of kernel extensions it needs to boot. If your Mac successfully starts up in Safe Boot mode, try restarting your Mac again in normal mode.