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My MacBook had Snow Leopard. I was trying to remove Windows 7 to make more space available. When I thought I had successfully removed Windows 7, I powered off the laptop and when I turned it back on, I have a black screen that says non-system disk press any key to reboot.

I have pressed a key and nothing happens. I've tried Control+R to bring up the recovery system and it brings be back to this screen. I've tried X which is supposed to force OS X to open and I get back to the black screen. I've tried holding down the Option button and it shows the Windows 7 option. Even after selecting that, I'm brought back to the black screen.

I don't have my Snow Leopard disc any longer and I just don't know what to do at this point.

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How did you remove Windows 7? – jornane Sep 2 '14 at 19:03
yes, probably the method used to remove windows 7 changed some configurations on the partitions. Bootcamp has a "remove windows" options that probably required, that is why is there. Bootcamp makes some funny partitioning when preparing the windows installation, in my case for example I used Windows 7 to create a partition out of free space and Mac didn't boot at all after that. Windows did warned me when applying these changes though. – adrianTNT Sep 12 '14 at 23:16

If you're seeing that error message on a black background in white letters, it means that your Mac is stuck trying to boot into BootCamp, but there's nothing to boot, since you've just removed Windows. What you need to do, is to tell your Mac to boot back into OS X. Try this:

  1. Power down your Mac and make sure it's turned off.
  2. Turn it back on, and when you hear the startup sound, hold down and Option (Alt) key on the keyboard.
  3. If you did everything correctly, you should see a list of disks you can boot from, including Macintosh HD (or whatever it's called if you renamed it in the past).
  4. When you're back in Mac OS X, fire up System Preferences and click the Startup disk control panel icon. Make sure that your Macintosh HD disk is selected as the default boot disk.
  5. Finally fire up BootCamp Assistant to completely remove all traces of the Windows partition off your hard drive. If you're brave and are sure what you're doing, you can also use Disk Utility for that, but be careful, it's not as straighforward to use as Bootcamp Assistant.

I hope this helps!

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After I held down the option button the only disk there is the windows and not the Macintosh HD at all. – snix83 Mar 6 '13 at 3:31
Even after selecting the windows disk I get the black screen again. – snix83 Mar 6 '13 at 3:33
It sounds like whatever you did to remove Windows 7 has also affected your Mac OS X installation. Do you have access to a Mac OS X installation disk or USB stick (any version)? If so, I suggest that you use it to gain access to your Mac partition, back it up, and reinstall Mac OS X. – Rouben Apr 29 '13 at 14:12
If you accidentally blew away the partition tables, you may need to use TestDisk to find and restore the partitions if other suggestions don't pan out. It might not work on the Mac partition, but it may be able to recover the Windows 7 one sufficiently to remove it properly. – GuitarPicker Apr 24 '15 at 16:23

That's happening because the boot order was not changed.

Go to BIOS (press F10 on startup, before the Windows boot logo), and reset all to default. (Tested in Windows 7, probably the same for all OS)

Manually revert boot order, not helping (You always got first one, instead of normal boot logo).

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