I believe that syncing your partition tables will help. This can be done with the partition tool after installing rEFIt. This will make sure that you GPT and MBR tables are the same. (rEFIt will show a “boot menu” after restarting your mac where you can choose to boot whichever partition you want. At the bottom of this screen there are some additional tools, one being the MBR sync tool.)

Secondly, there is the actual MBR boot code (aside from the partition table) that needs to exist in order for windows to operate. You can repair this by using the FIXMBR utility that is included as part of the recovery tools on your windows CD.

I made the mistake of trying to install ubuntu on my 17″ mbp and hosed the windows mbr. I avoided screwing up the os x boot by not installing a boot loader with ubuntu, fortunately.

All I need is a way to fix the mbr for the windows partition.

Holding down the alt key shows me os x and windows, but when windows is selected all I get is “an error occured loading the operating system” or something short like that. I can mount the NTFS partition, and r/w it with macFUSE, just can’t boot it.

I created a parted magic boot CD but don’t see an option to fix the mbr. Several other tools won’t work with the “hybrid” gpt – mbr scheme.

One article says to use the unix fdisk -u /dev/disk0 off the max os x install DVD. The 10.4.6 DVD has an fdisk but it complains it can’t find the mbr image in standalone/i386/boot0. So I don’t think fdisk was used on the mac as it appears to not be configured with correct file paths.

Anyway, if you could give me a pointer to a tool I might use to fix the mbr I would greatly appreciate it.

Thanks for the informative article!