I have a 2009 Mac Pro (MacPro4,1) which, until recently, had both OS X Yosemite and a Boot Camp install of Windows 10 on it. Shortly after I upgraded to El Capitan, I found that Boot Camp Assistant refused to run, reporting "This Mac does not support Boot Camp".

Furthermore, I am unable to use BootChamp to reboot into Windows, as it reports a cryptic message "Bless failed".

Any ideas what would cause Boot Camp to stop working?

  • Are you trying to install Windows? Or, is it that you can not boot to Windows? May 1, 2016 at 6:21
  • @DavidAnderson: The latter. Updated question to reflect this. May 7, 2016 at 3:37

1 Answer 1


The solution for fixing Boot Camp Assistant was the same as with previous versions of the OS: reset the NVRAM.

I found a discussion mentioning a similar problem with an upgrade to Yosemite here that I intiially disregarded as it referenced repairing permissions and running a Disk Verify, neither of which Disk Utility appears to support anymore.

As for BootChamp, it is no longer supported as of El Capitan. System Integrity Protection prevents it from running.

  • You can disable SIP if you want.
    – JMY1000
    May 7, 2016 at 5:45
  • After two years this answer is still useful. I have the same machine.
    – kometen
    Aug 1, 2018 at 7:08

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