Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

I needed to resize my Boot Camp partition so I used Gparted to move and resize it. This seemed to work, except that now I can't boot into Windows.

I can boot into OS X just fine. OS X can recognize the Boot Camp partition and view its contents. When I try to reboot into Windows, however I get the message:

No bootable device -- insert boot disk and press any key

The only solutions I've been able to find online suggest that the only way to fix this is to either clone the drive or remove the Windows partition and re-install it.

Is there any way to fix my Windows partition so that I don't have to reinstall Windows again?

share|improve this question
    
I was having a similar chain of errors when recovering my Boot Camp partition. I used some of this info and needed to add a step or two, but got it all back in working order. Posted here: Get Mac OS back onto MacBook and keep Windows 7 Boot Camp partition –  noahcoad May 23 '12 at 6:52
    
See the blog post Get Mac OS back onto MacBook and keep Windows 7 Boot Camp partition for detailed instructions. –  Aleksey K Oct 20 '12 at 13:30

3 Answers 3

up vote 9 down vote accepted

It might be that your Windows partition is just fine, but it's your Protective Master Boot Record that's screwed up. Macs use the more modern GUID Partition Table (GPT) format to define where each of the partitions are, but for Boot Camp booting into Windows, you need a fake version of a traditional Master Boot Record (MBR) on the drive.

Apple's Boot Camp Assistant takes care of creating this "Protective Master Boot Record" or "PMBR" as they call it. Apple's tools are aware of the need for keeping the GPT and PMBR in sync, but perhaps GParted wasn't so careful.

There are third-party tools such as rEFIt that, among other things, can probably help you get your GPT and your PMBR back in agreement after some other tool has messed them up.

Or you might try using Mac OS X v10.7.x (Lion)'s Disk Utility to repair the drive. Make sure you select the whole disk, not a partition.

Another fix might be to use Disk Utility to slightly resize a partition, so that it has to rewrite the GPT and PMBR.

share|improve this answer
    
Both you and Eli had the correct solution. rEFIt was able to sync my GPT and PMBR, which made Windows bootable again. I've accepted your answer because it helped me understand the issue in more detail so I know what went wrong. –  Dan Herbert Jan 4 '12 at 4:06
    
thanks so much! –  user115422 Feb 11 '13 at 0:04

Try installing rEFIt and using it to sync the GPT tables. Don't know if that will work, but it's worth a shot.

It could be that the Windows bootloader is messed up. I'd try booting from a Windows recovery CD/DVD and rebuilding the bootloader/MBR.

share|improve this answer

I had the same problem. Refit did not work for me, however I did the following steps and one of them seemed to fix it. Sorry I can't be more specific on which step it was

  1. Boot from the OSX lion DVD
  2. Repair the top level disk
  3. Resize the OSX parition slightly then resize back
  4. Boot into the windows 7 DVD and repair the boot loader problems, by going to "Repair your computer", selecting your Windows and "Startup Repair".
  5. Boot back into OSX and set bootcamp at the startup disk from the system preferences...
share|improve this answer

protected by Community Nov 2 '12 at 21:15

Thank you for your interest in this question. Because it has attracted low-quality answers, posting an answer now requires 10 reputation on this site.

Would you like to answer one of these unanswered questions instead?

Not the answer you're looking for? Browse other questions tagged or ask your own question.