I am trying to install OS X El Capitan on an early 2008 Mac Pro. I wiped the hard drive on the Mac and followed this tutorial to create a USB boot drive with El Capitan using a Macbook Air running El Capitan. I then place the USB into the Mac Pro and hold the option key during boot. The option to install El Captian from the USB stick appears and the window with a loading bar and the Apple logo appears. The loading bar loads 2/3 of the way and then the following screen appears.

enter image description here

This error is cryptic so I did some research online to see if any others have had this issue. Other have suggested to try another USB stick but this did not change the behavior. I've also read that this problem can occur with an incompatible version of OS X being installed. Is this possible?

Does anyone hae any idea how to fix this?

  • I've never got any Mac that was built with a Superdrive to boot properly off USB. I'd try putting the installer on another HD & boot from that… but you wiped your only boot drive already… Catch 22.
    – Tetsujin
    Feb 16, 2016 at 17:03

5 Answers 5


Probably you got a faulty SO image. You should try to re download the installation file from the App Store and/or try some other method to put the installer on the USB.


I had same issue on MacBook Pro 2007, actually this is oldest MBP that could run OS X 10.11.

After trying different solutions I had to boot up from current system, connect new empty HDD (actually it was SSD, but HDD will work too) and started install from downloaded application then chose new HDD as installation source and swaped disks after installation.

Hopes this helps.


If your machine is quite old you may first need to reinstall the copy of Lion / Mountain Lion that came with your machine, then upgrade to El Capitan using either your bootable USB stick, or just by using the normal Apple Store process.

Follow the Apple article Create a bootable installer for OSX to create a bootable USB stick from a freshly-downloaded copy of El Capitan.


I'm having the same problem on my MacPro(3,1) Early 2008, except my progress bar gets to about 55%. In verbose mode, it shows it's hanging at a DSMOS / Bluetooth error indefinitely. I suspect I may need to instead create a bootable Mountain Lion, or even Leopard image on my USB. I just dropped $1k on new memory and an SSD PCI Mercury Accelsior, so I'm not giving up yet on this 2008. lol


After failing to install the OS using multiple USB drives and slots, I was lucky enough to find an old OSX installation disk in the IT department at work and was able to install the OS.

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